id
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problem_number
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title
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statement
string
background
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difficulty_level_id
int64
status
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proposed_by
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proposed_year
int64
category_id
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set_id
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favorite_count
int64
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timestamp[s]
updated_at
timestamp[s]
published
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category
dict
difficulty
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set
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duplicates
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notes
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tags
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source_url
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1,964
EP-158
Erdős Problem #158
Let $A\subset \mathbb{N}$ be an infinite set such that, for any $n$, there are most $2$ solutions to $a+b=n$ with $a\leq b$. Must\[\liminf_{N\to\infty}\frac{\lvert A\cap \{1,\ldots,N\}\rvert}{N^{1/2}}=0?\]
Erdős Problems (#158, https://www.erdosproblems.com/158). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.158).
1
open
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/158", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "sidon-sets" ]
null
null
null
null
https://www.erdosproblems.com/158
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,965
EP-159
Erdős Problem #159
There exists some constant $c>0$ such that $$R(C_4,K_n) \ll n^{2-c}.$$
Erdős Problems (#159, https://www.erdosproblems.com/159). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.159).
1
open
null
null
3
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/159", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "graph-theory", "ramsey-theory" ]
null
null
null
null
https://www.erdosproblems.com/159
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,966
EP-160
Erdős Problem #160
Let $h(N)$ be the smallest $k$ such that $\{1,\ldots,N\}$ can be coloured with $k$ colours so that every four-term arithmetic progression must contain at least three distinct colours. Estimate $h(N)$.
Erdős Problems (#160, https://www.erdosproblems.com/160). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.160).
1
open
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/160", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/160
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,967
EP-161
Erdős Problem #161
Let $\alpha\in[0,1/2)$ and $n,t\geq 1$. Let $F^{(t)}(n,\alpha)$ be the smallest $m$ such that we can $2$-colour the edges of the complete $t$-uniform hypergraph on $n$ vertices such that if $X\subseteq [n]$ with $\lvert X\rvert \geq m$ then there are at least $\alpha \binom{\lvert X\rvert}{t}$ many $t$-subsets of $X$ o...
Erdős Problems (#161, https://www.erdosproblems.com/161). Maintainer status: OPEN. Erdős prize: $500. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.161).
1
partially_solved
null
null
3
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/161", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "combinatorics", "ramsey-theory", "discrepancy", "hypergraphs" ]
null
null
null
null
https://www.erdosproblems.com/161
Erdős Problems (erdosproblems.com)
$500
[]
null
null
null
null
null
null
null
null
null
null
1,968
EP-162
Erdős Problem #162
Let $\alpha>0$ and $n\geq 1$. Let $F(n,\alpha)$ be the largest $k$ such that there exists some 2-colouring of the edges of $K_n$ in which any induced subgraph $H$ on at least $k$ vertices contains more than $\alpha\binom{\lvert H\rvert}{2}$ many edges of each colour. Prove that for every fixed $0\leq \alpha \leq 1/2$,...
Erdős Problems (#162, https://www.erdosproblems.com/162). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.162).
1
partially_solved
null
null
3
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/162", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "combinatorics", "ramsey-theory", "discrepancy" ]
null
null
null
null
https://www.erdosproblems.com/162
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,969
EP-165
Erdős Problem #165
Give an asymptotic formula for $R(3,k)$.
Erdős Problems (#165, https://www.erdosproblems.com/165). Maintainer status: OPEN. Erdős prize: $250. OEIS: A000791.
1
open
null
null
3
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/165", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "graph-theory", "ramsey-theory" ]
null
null
null
null
https://www.erdosproblems.com/165
Erdős Problems (erdosproblems.com)
$250
[]
null
null
null
null
null
null
null
null
null
null
1,970
EP-168
Erdős Problem #168
Let $F(N)$ be the size of the largest subset of $\{1,\ldots,N\}$ which does not contain any set of the form $\{n,2n,3n\}$. What is\[ \lim_{N\to \infty}\frac{F(N)}{N}?\]Is this limit irrational?
Erdős Problems (#168, https://www.erdosproblems.com/168). Maintainer status: OPEN. OEIS: A004059, A057561, A094708, A386439. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.168).
1
partially_solved
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/168", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics" ]
null
null
null
null
https://www.erdosproblems.com/168
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,971
EP-169
Erdős Problem #169
Let $k\geq 3$ and $f(k)$ be the supremum of $\sum_{n\in A}\frac{1}{n}$ as $A$ ranges over all sets of positive integers which do not contain a $k$-term arithmetic progression. Estimate $f(k)$. Is\[\lim_{k\to \infty}\frac{f(k)}{\log W(k)}=\infty\]where $W(k)$ is the van der Waerden number?
Erdős Problems (#169, https://www.erdosproblems.com/169). Maintainer status: OPEN. OEIS: A005346.
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/169", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/169
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,972
EP-170
Erdős Problem #170
Let $F(N)$ be the smallest possible size of $A\subset \{0,1,\ldots,N\}$ such that $\{0,1,\ldots,N\}\subset A-A$. Find the value of\[\lim_{N\to \infty}\frac{F(N)}{N^{1/2}}.\]
Erdős Problems (#170, https://www.erdosproblems.com/170). Maintainer status: OPEN. sparse ruler problem OEIS: A046693. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.170).
1
open
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/170", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
sparse ruler problem
[ "erdos-problems", "additive-combinatorics" ]
null
null
null
null
https://www.erdosproblems.com/170
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,973
EP-172
Erdős Problem #172
Is it true that in any finite colouring of $\mathbb{N}$ there exist arbitrarily large finite $A$ such that all sums and products of distinct elements in $A$ are the same colour?
Erdős Problems (#172, https://www.erdosproblems.com/172). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.172).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/172", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics", "ramsey-theory" ]
null
null
null
null
https://www.erdosproblems.com/172
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,974
EP-173
Erdős Problem #173
In any $2$-colouring of $\mathbb{R}^2$, for all but at most one triangle $T$, there is a monochromatic congruent copy of $T$.
Erdős Problems (#173, https://www.erdosproblems.com/173). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.173).
1
open
null
null
3
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/173", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "geometry", "ramsey-theory" ]
null
null
null
null
https://www.erdosproblems.com/173
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,975
EP-174
Erdős Problem #174
A finite set $A\subset \mathbb{R}^n$ is called Ramsey if, for any $k\geq 1$, there exists some $d=d(A,k)$ such that in any $k$-colouring of $\mathbb{R}^d$ there exists a monochromatic copy of $A$. Characterise the Ramsey sets in $\mathbb{R}^n$.
Erdős Problems (#174, https://www.erdosproblems.com/174). Maintainer status: OPEN.
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/174", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "geometry", "ramsey-theory" ]
null
null
null
null
https://www.erdosproblems.com/174
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,976
EP-176
Erdős Problem #176
Let $N(k,\ell)$ be the minimal $N$ such that for any $f:\{1,\ldots,N\}\to\{-1,1\}$ there must exist a $k$-term arithmetic progression $P$ such that\[ \left\lvert \sum_{n\in P}f(n)\right\rvert\geq \ell.\]Find good upper bounds for $N(k,\ell)$. Is it true that for any $c>0$ there exists some $C>1$ such that\[N(k,ck)\leq ...
Erdős Problems (#176, https://www.erdosproblems.com/176). Maintainer status: OPEN.
1
open
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/176", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics", "arithmetic-progressions", "discrepancy" ]
null
null
null
null
https://www.erdosproblems.com/176
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,977
EP-177
Erdős Problem #177
Find the smallest $h(d)$ such that the following holds. There exists a function $f:\mathbb{N}\to\{-1,1\}$ such that, for every $d\geq 1$,\[\max_{P_d}\left\lvert \sum_{n\in P_d}f(n)\right\rvert\leq h(d),\]where $P_d$ ranges over all finite arithmetic progressions with common difference $d$.
Erdős Problems (#177, https://www.erdosproblems.com/177). Maintainer status: OPEN.
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/177", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "discrepancy", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/177
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,978
EP-180
Erdős Problem #180
If $\mathcal{F}$ is a finite set of finite graphs then $\mathrm{ex}(n;\mathcal{F})$ is the maximum number of edges a graph on $n$ vertices can have without containing any subgraphs from $\mathcal{F}$. Note that it is trivial that $\mathrm{ex}(n;\mathcal{F})\leq \mathrm{ex}(n;G)$ for every $G\in\mathcal{F}$. Is it true...
Erdős Problems (#180, https://www.erdosproblems.com/180). Maintainer status: DISPROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.180).
1
solved
null
null
3
8
0
0
2024-01-01T00:00:00
2026-09-27T00:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/180", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "graph-theory", "turan-number" ]
The maintained Erdős Problems source lists problem 180 as “disproved (Lean)” on 2026-09-27. The source marks a Lean verification of the resolution. **What remains.** No unresolved part of the stated question is identified in the cited result.
[ { "url": "https://www.erdosproblems.com/180", "label": "Erdős Problems #180: disproved (Lean)" }, { "url": "https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml", "label": "Erdős Problems machine-readable status list (snapshot checked 2026-09-27)" }, { "url": "https://hug...
2026-09-27T00:00:00
Erdős Problems #180: disproved (Lean): https://www.erdosproblems.com/180 Erdős Problems machine-readable status list (snapshot checked 2026-09-27): https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml
https://www.erdosproblems.com/180
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,979
EP-181
Erdős Problem #181
Let $Q_n$ be the $n$-dimensional hypercube graph (so that $Q_n$ has $2^n$ vertices and $n2^{n-1}$ edges). Prove that\[R(Q_n) \ll 2^n.\]
Erdős Problems (#181, https://www.erdosproblems.com/181). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.181).
1
open
null
null
3
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/181", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "graph-theory", "ramsey-theory" ]
null
null
null
null
https://www.erdosproblems.com/181
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,980
EP-183
Erdős Problem #183
Let $R(3;k)$ be the minimal $n$ such that if the edges of $K_n$ are coloured with $k$ colours then there must exist a monochromatic triangle. Determine\[\lim_{k\to \infty}R(3;k)^{1/k}.\]
Erdős Problems (#183, https://www.erdosproblems.com/183). Maintainer status: SOLVED (LEAN). Erdős prize: $250. OEIS: A003323. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.183).
1
solved
null
null
1
8
0
0
2024-01-01T00:00:00
2026-09-27T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/183", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "solved (Lean)" }
null
null
null
null
[ "erdos-problems", "graph-theory", "ramsey-theory" ]
The maintained Erdős Problems source lists problem 183 as “solved (Lean)” on 2026-09-27. The source marks a Lean verification of the resolution. **What remains.** No unresolved part of the stated question is identified in the cited result.
[ { "url": "https://www.erdosproblems.com/183", "label": "Erdős Problems #183: solved (Lean)" }, { "url": "https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml", "label": "Erdős Problems machine-readable status list (snapshot checked 2026-09-27)" }, { "url": "https://huggin...
2026-09-27T00:00:00
Erdős Problems #183: solved (Lean): https://www.erdosproblems.com/183 Erdős Problems machine-readable status list (snapshot checked 2026-09-27): https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml
https://www.erdosproblems.com/183
Erdős Problems (erdosproblems.com)
$250
[]
null
null
null
null
null
null
null
null
null
null
1,981
EP-184
Erdős Problem #184
Any graph on $n$ vertices can be decomposed into $O(n)$ many edge-disjoint cycles and edges.
Erdős Problems (#184, https://www.erdosproblems.com/184). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.184).
1
open
null
null
3
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/184", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
[Discussion #4 literature review, 2026-10-08] arXiv:1310.7082 is "Concentration of small Willmore spheres in Riemannian 3-manifolds" by P. Laurain and A. Mondino; cited paper (Conlon–Fox–Sudakov, "Cycle packing"): arXiv:1310.0632.
[ "erdos-problems", "graph-theory", "cycles" ]
null
null
null
null
https://www.erdosproblems.com/184
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,982
EP-187
Erdős Problem #187
Find the best function $f(d)$ such that, in any 2-colouring of the integers, at least one colour class contains an arithmetic progression with common difference $d$ of length $f(d)$ for infinitely many $d$.
Erdős Problems (#187, https://www.erdosproblems.com/187). Maintainer status: OPEN.
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/187", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics", "ramsey-theory", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/187
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,983
EP-188
Erdős Problem #188
What is the smallest $k$ such that $\mathbb{R}^2$ can be red/blue coloured with no pair of red points unit distance apart, and no $k$-term arithmetic progression of blue points with distance $1$?
Erdős Problems (#188, https://www.erdosproblems.com/188). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.188).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/188", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "geometry", "ramsey-theory" ]
null
null
null
null
https://www.erdosproblems.com/188
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,984
EP-190
Erdős Problem #190
Let $H(k)$ be the smallest $N$ such that in any finite colouring of $\{1,\ldots,N\}$ (into any number of colours) there is always either a monochromatic $k$-term arithmetic progression or a rainbow arithmetic progression (i.e. all elements are different colours). Estimate $H(k)$. Is it true that\[H(k)^{1/k}/k \to \inft...
Erdős Problems (#190, https://www.erdosproblems.com/190). Maintainer status: SOLVED (LEAN).
1
solved
null
null
3
8
0
0
2024-01-01T00:00:00
2026-09-27T00:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/190", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "solved (Lean)" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics", "arithmetic-progressions" ]
The maintained Erdős Problems source lists problem 190 as “solved (Lean)” on 2026-09-27. The source marks a Lean verification of the resolution. **What remains.** No unresolved part of the stated question is identified in the cited result.
[ { "url": "https://www.erdosproblems.com/190", "label": "Erdős Problems #190: solved (Lean)" }, { "url": "https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml", "label": "Erdős Problems machine-readable status list (snapshot checked 2026-09-27)" }, { "url": "https://huggin...
2026-09-27T00:00:00
Erdős Problems #190: solved (Lean): https://www.erdosproblems.com/190 Erdős Problems machine-readable status list (snapshot checked 2026-09-27): https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml
https://www.erdosproblems.com/190
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,985
EP-193
Erdős Problem #193
Let $S\subseteq \mathbb{Z}^3$ be a finite set and let $A=\{a_1,a_2,\ldots,\}\subset \mathbb{Z}^3$ be an infinite $S$-walk, so that $a_{i+1}-a_i\in S$ for all $i$. Must $A$ contain three collinear points?
Erdős Problems (#193, https://www.erdosproblems.com/193). Maintainer status: DISPROVED (LEAN). OEIS: A231255. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.193).
1
solved
null
null
2
8
0
0
2024-01-01T00:00:00
2026-09-27T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/193", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "geometry" ]
The maintained Erdős Problems source lists problem 193 as “disproved (Lean)” on 2026-09-27. The source marks a Lean verification of the resolution. **What remains.** No unresolved part of the stated question is identified in the cited result.
[ { "url": "https://www.erdosproblems.com/193", "label": "Erdős Problems #193: disproved (Lean)" }, { "url": "https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml", "label": "Erdős Problems machine-readable status list (snapshot checked 2026-09-27)" }, { "url": "https://hug...
2026-09-27T00:00:00
Erdős Problems #193: disproved (Lean): https://www.erdosproblems.com/193 Erdős Problems machine-readable status list (snapshot checked 2026-09-27): https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml
https://www.erdosproblems.com/193
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,986
EP-195
Erdős Problem #195
What is the largest $k$ such that in any permutation of $\mathbb{Z}$ there must exist a monotone $k$-term arithmetic progression $x_1<\cdots<x_k$?
Erdős Problems (#195, https://www.erdosproblems.com/195). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.195).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/195", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/195
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,987
EP-196
Erdős Problem #196
Must every permutation of $\mathbb{N}$ contain a monotone 4-term arithmetic progression? In other words, given a permutation $x$ of $\mathbb{N}$ must there be indices with either $i<j<k<l$ or $i>j>k>l$ such that $x_i,x_j,x_k,x_l$ are an arithmetic progression?
Erdős Problems (#196, https://www.erdosproblems.com/196). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.196).
1
open
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/196", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/196
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,988
EP-197
Erdős Problem #197
Can $\mathbb{N}$ be partitioned into two sets, each of which can be permuted to avoid monotone 3-term arithmetic progressions?
Erdős Problems (#197, https://www.erdosproblems.com/197). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.197).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/197", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/197
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,989
EP-200
Erdős Problem #200
Does the longest arithmetic progression of primes in $\{1,\ldots,N\}$ have length $o(\log N)$?
Erdős Problems (#200, https://www.erdosproblems.com/200). Maintainer status: OPEN. OEIS: A005115. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.200).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/200", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "primes", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/200
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,990
EP-201
Erdős Problem #201
Let $G_k(N)$ be such that any set of $N$ integers contains a subset of size at least $G_k(N)$ which does not contain a $k$-term arithmetic progression. Determine the size of $G_k(N)$. How does it relate to $R_k(N)$, the size of the largest subset of $\{1,\ldots,N\}$ without a $k$-term arithmetic progression? Is it true...
Erdős Problems (#201, https://www.erdosproblems.com/201). Maintainer status: OPEN. OEIS: A003002, A003003, A003004, A003005.
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/201", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/201
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,991
EP-202
Erdős Problem #202
Let $n_1<\cdots < n_r\leq N$ with associated $a_i\pmod{n_i}$ such that the congruence classes are disjoint (that is, every integer is $\equiv a_i\pmod{n_i}$ for at most one $1\leq i\leq r$). How large can $r$ be in terms of $N$?
Erdős Problems (#202, https://www.erdosproblems.com/202). Maintainer status: SOLVED (LEAN). OEIS: A389975. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.202).
1
solved
null
null
1
8
0
0
2024-01-01T00:00:00
2026-09-27T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/202", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "solved (Lean)" }
null
null
null
null
[ "erdos-problems", "covering-systems" ]
The maintained Erdős Problems source lists problem 202 as “solved (Lean)” on 2026-09-27. The source marks a Lean verification of the resolution. **What remains.** No unresolved part of the stated question is identified in the cited result.
[ { "url": "https://www.erdosproblems.com/202", "label": "Erdős Problems #202: solved (Lean)" }, { "url": "https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml", "label": "Erdős Problems machine-readable status list (snapshot checked 2026-09-27)" }, { "url": "https://huggin...
2026-09-27T00:00:00
Erdős Problems #202: solved (Lean): https://www.erdosproblems.com/202 Erdős Problems machine-readable status list (snapshot checked 2026-09-27): https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml
https://www.erdosproblems.com/202
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,992
EP-203
Erdős Problem #203
Is there an integer $m\geq 1$ with $(m,6)=1$ such that none of $2^k3^\ell m+1$ are prime, for any $k,\ell\geq 0$?
Erdős Problems (#203, https://www.erdosproblems.com/203). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.203).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/203", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "primes", "covering-systems" ]
null
null
null
null
https://www.erdosproblems.com/203
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,993
EP-208
Erdős Problem #208
Let $s_1<s_2<\cdots$ be the sequence of squarefree numbers. Is it true that, for any $\epsilon>0$ and large $n$,\[s_{n+1}-s_n \ll_\epsilon s_n^{\epsilon}?\]Is it true that\[s_{n+1}-s_n \leq (1+o(1))\frac{\pi^2}{6}\frac{\log s_n}{\log\log s_n}?\]
Erdős Problems (#208, https://www.erdosproblems.com/208). Maintainer status: OPEN. OEIS: A005117, A076259. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.208).
1
open
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/208", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory" ]
null
null
null
null
https://www.erdosproblems.com/208
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,994
EP-212
Erdős Problem #212
Is there a dense subset of $\mathbb{R}^2$ such that all pairwise distances are rational?
Erdős Problems (#212, https://www.erdosproblems.com/212). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.212).
1
open
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/212", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "geometry", "distances" ]
null
null
null
null
https://www.erdosproblems.com/212
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,995
EP-213
Erdős Problem #213
Let $n\geq 4$. Are there $n$ points in $\mathbb{R}^2$, no three on a line and no four on a circle, such that all pairwise distances are integers?
Erdős Problems (#213, https://www.erdosproblems.com/213). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.213).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/213", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "geometry", "distances" ]
null
null
null
null
https://www.erdosproblems.com/213
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,996
EP-217
Erdős Problem #217
For which $n$ are there $n$ points in $\mathbb{R}^2$, no three on a line and no four on a circle, which determine $n-1$ distinct distances and so that (in some ordering of the distances) the $i$th distance occurs $i$ times?
Erdős Problems (#217, https://www.erdosproblems.com/217). Maintainer status: OPEN.
1
open
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/217", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "geometry", "distances" ]
null
null
null
null
https://www.erdosproblems.com/217
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,997
EP-218
Erdős Problem #218
Let $d_n=p_{n+1}-p_n$. The set of $n$ such that $d_{n+1}\geq d_n$ has density $1/2$, and similarly for $d_{n+1}\leq d_n$. Furthermore, there are infinitely many $n$ such that $d_{n+1}=d_n$.
Erdős Problems (#218, https://www.erdosproblems.com/218). Maintainer status: OPEN. OEIS: A333230, A333231, A064113. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.218).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/218", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "primes" ]
null
null
null
null
https://www.erdosproblems.com/218
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,998
EP-222
Erdős Problem #222
Let $n_1<n_2<\cdots$ be the sequence of integers which are the sum of two squares. Explore the behaviour of (i.e. find good upper and lower bounds for) the consecutive differences $n_{k+1}-n_k$.
Erdős Problems (#222, https://www.erdosproblems.com/222). Maintainer status: OPEN. OEIS: A001481, A256435.
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/222", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "squares" ]
null
null
null
null
https://www.erdosproblems.com/222
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
1,999
EP-233
Erdős Problem #233
Let $d_n=p_{n+1}-p_n$, where $p_n$ is the $n$th prime. Prove that\[\sum_{1\leq n\leq N}d_n^2 \ll N(\log N)^2.\]
Erdős Problems (#233, https://www.erdosproblems.com/233). Maintainer status: OPEN. OEIS: A074741. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.233).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/233", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "primes" ]
null
null
null
null
https://www.erdosproblems.com/233
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,000
EP-234
Erdős Problem #234
For every $c\geq 0$ the density $f(c)$ of integers for which\[\frac{p_{n+1}-p_n}{\log n}< c\]exists and is a continuous function of $c$.
Erdős Problems (#234, https://www.erdosproblems.com/234). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.234).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/234", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "primes" ]
null
null
null
null
https://www.erdosproblems.com/234
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,001
EP-236
Erdős Problem #236
Let $f(n)$ count the number of solutions to $n=p+2^k$ for prime $p$ and $k\geq 0$. Is it true that $f(n)=o(\log n)$?
Erdős Problems (#236, https://www.erdosproblems.com/236). Maintainer status: OPEN. OEIS: A039669, A109925. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.236).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/236", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "primes" ]
null
null
null
null
https://www.erdosproblems.com/236
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,002
EP-238
Erdős Problem #238
Let $c_1,c_2>0$. Is it true that, for any sufficiently large $x$, there exist more than $c_1\log x$ many consecutive primes $\leq x$ such that the difference between any two is $>c_2$?
Erdős Problems (#238, https://www.erdosproblems.com/238). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.238).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/238", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "primes" ]
null
null
null
null
https://www.erdosproblems.com/238
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,003
EP-241
Erdős Problem #241
Let $f(N)$ be the maximum size of $A\subseteq \{1,\ldots,N\}$ such that the sums $a+b+c$ with $a,b,c\in A$ are all distinct (aside from the trivial coincidences). Is it true that\[ f(N)\sim N^{1/3}?\]
Erdős Problems (#241, https://www.erdosproblems.com/241). Maintainer status: OPEN. Erdős prize: $100. OEIS: A387704. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.241).
1
open
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/241", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics", "sidon-sets" ]
null
null
null
null
https://www.erdosproblems.com/241
Erdős Problems (erdosproblems.com)
$100
[]
null
null
null
null
null
null
null
null
null
null
2,004
EP-243
Erdős Problem #243
Let $1\leq a_1<a_2<\cdots$ be a sequence of integers such that\[\lim_{n\to \infty}\frac{a_n}{a_{n-1}^2}=1\]and $\sum\frac{1}{a_n}\in \mathbb{Q}$. Then, for all sufficiently large $n\geq 1$,\[ a_n = a_{n-1}^2-a_{n-1}+1.\]
Erdős Problems (#243, https://www.erdosproblems.com/243). Maintainer status: OPEN. OEIS: A000058. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.243).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/243", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/243
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,005
EP-244
Erdős Problem #244
Let $C>1$. Does the set of integers of the form $p+\lfloor C^k\rfloor$, for some prime $p$ and $k\geq 0$, have density $>0$?
Erdős Problems (#244, https://www.erdosproblems.com/244). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.244).
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/244", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "primes" ]
null
null
null
null
https://www.erdosproblems.com/244
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,006
EP-247
Erdős Problem #247
Let $1\leq a_1<a_2<\cdots$ be a sequence of integers such that\[\limsup \frac{a_n}{n}=\infty.\]Is\[\sum_{n=1}^\infty \frac{1}{2^{a_n}}\]transcendental?
Erdős Problems (#247, https://www.erdosproblems.com/247). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.247).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/247", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/247
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,007
EP-249
Erdős Problem #249
Is\[\sum_n \frac{\phi(n)}{2^n}\]irrational? Here $\phi$ is the Euler totient function.
Erdős Problems (#249, https://www.erdosproblems.com/249). Maintainer status: OPEN. OEIS: A256936. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.249).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/249", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/249
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,008
EP-251
Erdős Problem #251
Is\[\sum \frac{p_n}{2^n}\]irrational? (Here $p_n$ is the $n$th prime.)
Erdős Problems (#251, https://www.erdosproblems.com/251). Maintainer status: OPEN. OEIS: A098990. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.251).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/251", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/251
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,009
EP-252
Erdős Problem #252
Let $k\geq 1$ and $\sigma_k(n)=\sum_{d\mid n}d^k$. Is\[\sum \frac{\sigma_k(n)}{n!}\]irrational?
Erdős Problems (#252, https://www.erdosproblems.com/252). Maintainer status: OPEN. OEIS: A227988, A227989, A307036, A359060. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.252).
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/252", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/252
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,010
EP-254
Erdős Problem #254
Let $A\subseteq \mathbb{N}$ be such that\[\lvert A\cap [1,2x]\rvert -\lvert A\cap [1,x]\rvert \to \infty\textrm{ as }x\to \infty\]and\[\sum_{n\in A} \{ \theta n\}=\infty\]for every $\theta\in (0,1)$, where $\{x\}$ is the distance of $x$ from the nearest integer. Then every sufficiently large integer is the sum of disti...
Erdős Problems (#254, https://www.erdosproblems.com/254). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.254).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/254", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory" ]
null
null
null
null
https://www.erdosproblems.com/254
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,011
EP-256
Erdős Problem #256
Let $n\geq 1$ and $f(n)$ be maximal such that for any integers $1\leq a_1\leq \cdots \leq a_n$ we have\[\max_{\lvert z\rvert=1}\left\lvert \prod_{i}(1-z^{a_i})\right\rvert\geq f(n).\]Estimate $f(n)$ - in particular, is it true that there exists some constant $c>0$ such that\[\log f(n) \gg n^c?\]
Erdős Problems (#256, https://www.erdosproblems.com/256). Maintainer status: OPEN.
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/256", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "analysis" ]
null
null
null
null
https://www.erdosproblems.com/256
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,012
EP-257
Erdős Problem #257
Let $A\subseteq \mathbb{N}$ be an infinite set. Is\[\sum_{n\in A}\frac{1}{2^n-1}\]irrational?
Erdős Problems (#257, https://www.erdosproblems.com/257). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.257).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/257", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/257
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,013
EP-258
Erdős Problem #258
Let $a_1,a_2,\ldots$ be a sequence of positive integers with $a_n\to \infty$. Is\[\sum_{n} \frac{\tau(n)}{a_1\cdots a_n}\]irrational, where $\tau(n)$ is the number of divisors of $n$?
Erdős Problems (#258, https://www.erdosproblems.com/258). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.258).
1
solved
null
null
1
8
0
0
2024-01-01T00:00:00
2026-09-27T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/258", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "irrationality" ]
The maintained Erdős Problems source lists problem 258 as “proved (Lean)” on 2026-09-27. The source marks a Lean verification of the resolution. **What remains.** No unresolved part of the stated question is identified in the cited result.
[ { "url": "https://www.erdosproblems.com/258", "label": "Erdős Problems #258: proved (Lean)" }, { "url": "https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml", "label": "Erdős Problems machine-readable status list (snapshot checked 2026-09-27)" }, { "url": "https://huggin...
2026-09-27T00:00:00
Erdős Problems #258: proved (Lean): https://www.erdosproblems.com/258 Erdős Problems machine-readable status list (snapshot checked 2026-09-27): https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml
https://www.erdosproblems.com/258
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,014
EP-260
Erdős Problem #260
Let $a_1<a_2<\cdots$ be an increasing sequence such that $a_n/n\to \infty$. Is the sum\[\sum_n \frac{a_n}{2^{a_n}}\]irrational?
Erdős Problems (#260, https://www.erdosproblems.com/260). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.260).
1
open
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/260", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/260
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,015
EP-261
Erdős Problem #261
Are there infinitely many $n$ such that there exists some $t\geq 2$ and distinct integers $a_1,\ldots,a_t\geq 1$ such that\[\frac{n}{2^n}=\sum_{1\leq k\leq t}\frac{a_k}{2^{a_k}}?\]Is this true for all $n$? Is there a rational $x$ such that\[x = \sum_{k=1}^\infty \frac{a_k}{2^{a_k}}\]has at least $2^{\aleph_0}$ solution...
Erdős Problems (#261, https://www.erdosproblems.com/261). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.261).
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/261", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory" ]
null
null
null
null
https://www.erdosproblems.com/261
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,016
EP-263
Erdős Problem #263
Let $a_n$ be an increasing sequence of positive integers such that for every sequence of positive integers $b_n$ with $b_n/a_n\to 1$ the sum\[\sum\frac{1}{b_n}\]is irrational. Is $a_n=2^{2^n}$ such a sequence? Must such a sequence satisfy $a_n^{1/n}\to \infty$?
Erdős Problems (#263, https://www.erdosproblems.com/263). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.263).
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/263", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/263
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,017
EP-264
Erdős Problem #264
Let $a_n$ be a sequence of positive integers such that for every bounded sequence of integers $b_n$ (with $a_n+b_n\neq 0$ and $b_n\neq 0$ for all $n$) the sum\[\sum \frac{1}{a_n+b_n}\]is irrational. Are $a_n=2^n$ or $a_n=n!$ examples of such a sequence?
Erdős Problems (#264, https://www.erdosproblems.com/264). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.264).
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/264", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/264
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,018
EP-265
Erdős Problem #265
Let $1\leq a_1<a_2<\cdots$ be an increasing sequence of integers. How fast can $a_n\to \infty$ grow if\[\sum\frac{1}{a_n}\quad\textrm{and}\quad\sum\frac{1}{a_n-1}\]are both rational?
Erdős Problems (#265, https://www.erdosproblems.com/265). Maintainer status: OPEN. ambiguous statement
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/265", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
ambiguous statement
[ "erdos-problems", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/265
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,019
EP-267
Erdős Problem #267
Let $F_1=F_2=1$ and $F_{n+1}=F_n+F_{n-1}$ be the Fibonacci sequence. Let $n_1<n_2<\cdots $ be an infinite sequence with $n_{k+1}/n_k \geq c>1$. Must\[\sum_k\frac{1}{F_{n_k}}\]be irrational?
Erdős Problems (#267, https://www.erdosproblems.com/267). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.267).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/267", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/267
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,020
EP-269
Erdős Problem #269
Let $P$ be a finite set of primes with $\lvert P\rvert \geq 2$ and let $\{a_1<a_2<\cdots\}=\{ n\in \mathbb{N}: \textrm{if }p\mid n\textrm{ then }p\in P\}$. Is the sum\[\sum_{n=1}^\infty \frac{1}{[a_1,\ldots,a_n]},\]where $[a_1,\ldots,a_n]$ is the lowest common multiple of $a_1,\ldots,a_n$, irrational?
Erdős Problems (#269, https://www.erdosproblems.com/269). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.269).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/269", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/269
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,021
EP-271
Erdős Problem #271
Let $A(n)=\{a_0<a_1<\cdots\}$ be the sequence defined by $a_0=0$ and $a_1=n$, and for $k\geq 1$ define $a_{k+1}$ as the least positive integer such that there is no three-term arithmetic progression in $\{a_0,\ldots,a_{k+1}\}$. Can the $a_k$ be explicitly determined? How fast do they grow?
Erdős Problems (#271, https://www.erdosproblems.com/271). Maintainer status: OPEN. Stanley sequences OEIS: A005487.
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/271", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
Stanley sequences
[ "erdos-problems", "additive-combinatorics", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/271
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,022
EP-272
Erdős Problem #272
Let $N\geq 1$. What is the largest $t$ such that there are $A_1,\ldots,A_t\subseteq \{1,\ldots,N\}$ with $A_i\cap A_j$ a non-empty arithmetic progression for all $i\neq j$?
Erdős Problems (#272, https://www.erdosproblems.com/272). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.272).
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/272", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/272
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,023
EP-273
Erdős Problem #273
Is there a covering system all of whose moduli are of the form $p-1$ for some primes $p\geq 5$?
Erdős Problems (#273, https://www.erdosproblems.com/273). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.273).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/273", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "covering-systems" ]
null
null
null
null
https://www.erdosproblems.com/273
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,024
EP-274
Erdős Problem #274
If $G$ is a group then can there exist an exact covering of $G$ by more than one cosets of different sizes? (i.e. each element is contained in exactly one of the cosets)
Erdős Problems (#274, https://www.erdosproblems.com/274). Maintainer status: OPEN. Herzog-Schönheim conjecture Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.274).
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/274", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
Herzog-Schönheim conjecture
[ "erdos-problems", "group-theory", "covering-systems" ]
null
null
null
null
https://www.erdosproblems.com/274
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,025
EP-276
Erdős Problem #276
Is there an infinite Lucas sequence $a_0,a_1,\ldots$ where $a_{n+2}=a_{n+1}+a_n$ for $n\geq 0$ such that all $a_k$ are composite, and yet no integer has a common factor with every term of the sequence?
Erdős Problems (#276, https://www.erdosproblems.com/276). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.276).
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/276", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "covering-systems" ]
null
null
null
null
https://www.erdosproblems.com/276
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,026
EP-278
Erdős Problem #278
Let $A=\{n_1<\cdots<n_r\}$ be a finite set of positive integers. What is the maximum density of integers covered by a suitable choice of congruences $a_i\pmod{n_i}$? Is the minimum density achieved when all the $a_i$ are equal?
Erdős Problems (#278, https://www.erdosproblems.com/278). Maintainer status: OPEN.
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2026-09-27T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/278", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "covering-systems" ]
Maximum-density half: an exact characterisation and a fixed-parameter exact algorithm (2^{O(r^2)} poly(input)); the minimum half was settled by Simpson (1986). Whether an exact algorithm counts as an answer to 'what is the maximum density' is for the maintainers to judge. Alper Ferudun (2026), unrefereed preprint with ...
[ { "url": "https://doi.org/10.5281/zenodo.22244392", "label": "Alper Ferudun (2026), An Exact Fixed-Parameter Algorithm for Extremal Unions of Residue Classes — unrefereed preprint" }, { "url": "https://eulersolve.org/papers/ep-278/", "label": "EulerSolve paper page and verification materials" ...
2026-09-27T00:00:00
null
https://www.erdosproblems.com/278
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,027
EP-279
Erdős Problem #279
Let $k\geq 3$. Is there a choice of congruence classes $a_p\pmod{p}$ for every prime $p$ such that all sufficiently large integers can be written as $a_p+tp$ for some prime $p$ and integer $t\geq k$?
Erdős Problems (#279, https://www.erdosproblems.com/279). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.279).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/279", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "covering-systems", "primes" ]
null
null
null
null
https://www.erdosproblems.com/279
Erdős Problems (erdosproblems.com)
null
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2,028
EP-281
Erdős Problem #281
Let $n_1<n_2<\cdots$ be an infinite sequence such that, for any choice of congruence classes $a_i\pmod{n_i}$, the set of integers not satisfying any of the congruences $a_i\pmod{n_i}$ has density $0$. Is it true that for every $\epsilon>0$ there exists some $k$ such that, for every choice of congruence classes $a_i$, ...
Erdős Problems (#281, https://www.erdosproblems.com/281). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.281).
1
solved
null
null
1
8
0
0
2024-01-01T00:00:00
2026-09-27T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/281", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "covering-systems" ]
The maintained Erdős Problems source lists problem 281 as “proved (Lean)” on 2026-09-27. The source marks a Lean verification of the resolution. **What remains.** No unresolved part of the stated question is identified in the cited result.
[ { "url": "https://www.erdosproblems.com/281", "label": "Erdős Problems #281: proved (Lean)" }, { "url": "https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml", "label": "Erdős Problems machine-readable status list (snapshot checked 2026-09-27)" }, { "url": "https://huggin...
2026-09-27T00:00:00
Erdős Problems #281: proved (Lean): https://www.erdosproblems.com/281 Erdős Problems machine-readable status list (snapshot checked 2026-09-27): https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml
https://www.erdosproblems.com/281
Erdős Problems (erdosproblems.com)
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[]
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null
2,029
EP-282
Erdős Problem #282
Let $A\subseteq \mathbb{N}$ be an infinite set and consider the following greedy algorithm for a rational $x\in (0,1)$: choose the minimal $n\in A$ such that $n\geq 1/x$ and repeat with $x$ replaced by $x-\frac{1}{n}$. If this terminates after finitely many steps then this produces a representation of $x$ as the sum of...
Erdős Problems (#282, https://www.erdosproblems.com/282). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.282).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/282", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
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null
https://www.erdosproblems.com/282
Erdős Problems (erdosproblems.com)
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[]
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2,030
EP-283
Erdős Problem #283
Let $p:\mathbb{Z}\to \mathbb{Z}$ be a polynomial whose leading coefficient is positive and such that there exists no $d\geq 2$ with $d\mid p(n)$ for all $n\geq 1$. Is it true that, for all sufficiently large $m$, there exist integers $1\leq n_1<\cdots <n_k$ such that\[1=\frac{1}{n_1}+\cdots+\frac{1}{n_k}\]and\[m=p(n_1)...
Erdős Problems (#283, https://www.erdosproblems.com/283). Maintainer status: PROVED (LEAN). OEIS: A380791. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.283).
1
solved
null
null
1
8
0
0
2024-01-01T00:00:00
2026-09-27T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/283", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
The maintained Erdős Problems source lists problem 283 as “proved (Lean)” on 2026-09-27. The source marks a Lean verification of the resolution. **What remains.** No unresolved part of the stated question is identified in the cited result.
[ { "url": "https://www.erdosproblems.com/283", "label": "Erdős Problems #283: proved (Lean)" }, { "url": "https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml", "label": "Erdős Problems machine-readable status list (snapshot checked 2026-09-27)" }, { "url": "https://huggin...
2026-09-27T00:00:00
Erdős Problems #283: proved (Lean): https://www.erdosproblems.com/283 Erdős Problems machine-readable status list (snapshot checked 2026-09-27): https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml
https://www.erdosproblems.com/283
Erdős Problems (erdosproblems.com)
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[]
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2,031
EP-288
Erdős Problem #288
Is it true that there are only finitely many pairs of intervals $I_1,I_2$ such that\[\sum_{n_1\in I_1}\frac{1}{n_1}+\sum_{n_2\in I_2}\frac{1}{n_2}\in \mathbb{N}?\]
Erdős Problems (#288, https://www.erdosproblems.com/288). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.288).
1
open
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/288", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
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null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
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null
https://www.erdosproblems.com/288
Erdős Problems (erdosproblems.com)
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[]
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2,032
EP-289
Erdős Problem #289
Is it true that, for all sufficiently large $k$, there exist finite intervals $I_1,\ldots,I_k\subset \mathbb{N}$, distinct, not overlapping or adjacent, with $\lvert I_i\rvert \geq 2$ for $1\leq i\leq k$ such that\[1=\sum_{i=1}^k \sum_{n\in I_i}\frac{1}{n}?\]
Erdős Problems (#289, https://www.erdosproblems.com/289). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.289).
1
open
null
null
3
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/289", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
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null
[ "erdos-problems", "number-theory", "unit-fractions" ]
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null
https://www.erdosproblems.com/289
Erdős Problems (erdosproblems.com)
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2,033
EP-291
Erdős Problem #291
Let $n\geq 1$ and define $L_n$ to be the least common multiple of $\{1,\ldots,n\}$ and $a_n$ by\[\sum_{1\leq k\leq n}\frac{1}{k}=\frac{a_n}{L_n}.\]Is it true that $(a_n,L_n)=1$ and $(a_n,L_n)>1$ both occur for infinitely many $n$?
Erdős Problems (#291, https://www.erdosproblems.com/291). Maintainer status: OPEN. OEIS: A110566. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.291).
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/291", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
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null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
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null
https://www.erdosproblems.com/291
Erdős Problems (erdosproblems.com)
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2,034
EP-293
Erdős Problem #293
Let $k\geq 1$ and let $v(k)$ be the minimal integer which does not appear as some $n_i$ in a solution to\[1=\frac{1}{n_1}+\cdots+\frac{1}{n_k}\]with $1\leq n_1<\cdots <n_k$. Estimate the growth of $v(k)$.
Erdős Problems (#293, https://www.erdosproblems.com/293). Maintainer status: OPEN. ambiguous statement
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/293", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
ambiguous statement
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
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null
https://www.erdosproblems.com/293
Erdős Problems (erdosproblems.com)
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2,035
EP-295
Erdős Problem #295
Let $N\geq 1$ and let $k(N)$ denote the smallest $k$ such that there exist $N\leq n_1<\cdots <n_k$ with\[1=\frac{1}{n_1}+\cdots+\frac{1}{n_k}.\]Is it true that\[\lim_{N\to \infty} k(N)-(e-1)N=\infty?\]
Erdős Problems (#295, https://www.erdosproblems.com/295). Maintainer status: OPEN. OEIS: A192881. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.295).
1
open
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/295", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
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null
https://www.erdosproblems.com/295
Erdős Problems (erdosproblems.com)
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[]
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2,036
EP-301
Erdős Problem #301
Let $f(N)$ be the size of the largest $A\subseteq \{1,\ldots,N\}$ such that there are no solutions to\[\frac{1}{a}= \frac{1}{b_1}+\cdots+\frac{1}{b_k}\]with distinct $a,b_1,\ldots,b_k\in A$? Estimate $f(N)$. In particular, is it true that $f(N)=(\tfrac{1}{2}+o(1))N$?
Erdős Problems (#301, https://www.erdosproblems.com/301). Maintainer status: OPEN. OEIS: A390394.
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/301", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
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null
https://www.erdosproblems.com/301
Erdős Problems (erdosproblems.com)
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[]
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2,037
EP-302
Erdős Problem #302
Let $f(N)$ be the size of the largest $A\subseteq \{1,\ldots,N\}$ such that there are no solutions to\[\frac{1}{a}= \frac{1}{b}+\frac{1}{c}\]with distinct $a,b,c\in A$? Estimate $f(N)$. In particular, is $f(N)=(\tfrac{1}{2}+o(1))N$?
Erdős Problems (#302, https://www.erdosproblems.com/302). Maintainer status: OPEN. OEIS: A390395. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.302).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/302", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/302
Erdős Problems (erdosproblems.com)
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[]
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2,038
EP-304
Erdős Problem #304
For integers $1\leq a<b$ let $N(a,b)$ denote the minimal $k$ such that there exist integers $1<n_1<\cdots<n_k$ with\[\frac{a}{b}=\frac{1}{n_1}+\cdots+\frac{1}{n_k}.\]Estimate $N(b)=\max_{1\leq a<b}N(a,b)$. Is it true that $N(b) \ll \log\log b$?
Erdős Problems (#304, https://www.erdosproblems.com/304). Maintainer status: OPEN. OEIS: A097847, A097849. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.304).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/304", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/304
Erdős Problems (erdosproblems.com)
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[]
null
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2,039
EP-306
Erdős Problem #306
Let $a/b\in \mathbb{Q}_{>0}$ with $b$ squarefree. Are there integers $1<n_1<\cdots<n_k$, each the product of two distinct primes, such that\[\frac{a}{b}=\frac{1}{n_1}+\cdots+\frac{1}{n_k}?\]
Erdős Problems (#306, https://www.erdosproblems.com/306). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.306).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/306", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/306
Erdős Problems (erdosproblems.com)
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[]
null
null
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2,040
EP-311
Erdős Problem #311
Let $\delta(N)$ be the minimal non-zero value of $\lvert 1-\sum_{n\in A}\frac{1}{n}\rvert$ as $A$ ranges over all subsets of $\{1,\ldots,N\}$. Is it true that\[\delta(N)=e^{-(c+o(1))N}\]for some constant $c\in (0,1)$?
Erdős Problems (#311, https://www.erdosproblems.com/311). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.311).
1
open
null
null
3
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/311", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/311
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,041
EP-312
Erdős Problem #312
Does there exist some $c>0$ such that, for any $K>1$, whenever $A$ is a sufficiently large finite multiset of positive integers with $\sum_{n\in A}\frac{1}{n}>K$ there exists some $S\subseteq A$ such that\[1-e^{-cK} < \sum_{n\in S}\frac{1}{n}\leq 1?\]
Erdős Problems (#312, https://www.erdosproblems.com/312). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.312).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/312", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/312
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,042
EP-313
Erdős Problem #313
Are there infinitely many solutions to\[\frac{1}{p_1}+\cdots+\frac{1}{p_k}=1-\frac{1}{m},\]where $m\geq 2$ is an integer and $p_1<\cdots<p_k$ are distinct primes?
Erdős Problems (#313, https://www.erdosproblems.com/313). Maintainer status: OPEN. OEIS: A054377. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.313).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/313", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/313
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
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null
null
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null
2,043
EP-317
Erdős Problem #317
Is there some constant $c>0$ such that for every $n\geq 1$ there exists some $\delta_k\in \{-1,0,1\}$ for $1\leq k\leq n$ with\[0< \left\lvert \sum_{1\leq k\leq n}\frac{\delta_k}{k}\right\rvert < \frac{c}{2^n}?\]Is it true that for sufficiently large $n$, for any $\delta_k\in \{-1,0,1\}$,\[\left\lvert \sum_{1\leq k\leq...
Erdős Problems (#317, https://www.erdosproblems.com/317). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.317).
1
open
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/317", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/317
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
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null
2,044
EP-318
Erdős Problem #318
Let $A\subseteq \mathbb{N}$ be an infinite arithmetic progression and $f:A\to \{-1,1\}$ be a non-constant function. Must there exist a finite non-empty $S\subset A$ such that\[\sum_{n\in S}\frac{f(n)}{n}=0?\]What about if $A$ is an arbitrary set of positive density? What if $A$ is the set of squares excluding $1$?
Erdős Problems (#318, https://www.erdosproblems.com/318). Maintainer status: SOLVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.318).
1
solved
null
null
3
8
0
0
2024-01-01T00:00:00
2026-09-27T00:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/318", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "solved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
The maintained Erdős Problems source lists problem 318 as “solved (Lean)” on 2026-09-27. The source marks a Lean verification of the resolution. **What remains.** No unresolved part of the stated question is identified in the cited result.
[ { "url": "https://www.erdosproblems.com/318", "label": "Erdős Problems #318: solved (Lean)" }, { "url": "https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml", "label": "Erdős Problems machine-readable status list (snapshot checked 2026-09-27)" }, { "url": "https://huggin...
2026-09-27T00:00:00
Erdős Problems #318: solved (Lean): https://www.erdosproblems.com/318 Erdős Problems machine-readable status list (snapshot checked 2026-09-27): https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml
https://www.erdosproblems.com/318
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,045
EP-319
Erdős Problem #319
What is the size of the largest $A\subseteq \{1,\ldots,N\}$ such that there is a function $\delta:A\to \{-1,1\}$ such that\[\sum_{n\in A}\frac{\delta_n}{n}=0\]and\[\sum_{n\in A'}\frac{\delta_n}{n}\neq 0\]for all non-empty $A'\subsetneq A$?
Erdős Problems (#319, https://www.erdosproblems.com/319). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.319).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/319", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/319
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,046
EP-320
Erdős Problem #320
Let $S(N)$ count the number of distinct sums of the form $\sum_{n\in A}\frac{1}{n}$ for $A\subseteq \{1,\ldots,N\}$. Estimate $S(N)$.
Erdős Problems (#320, https://www.erdosproblems.com/320). Maintainer status: SOLVED. OEIS: A072207.
1
solved
null
null
2
8
0
0
2024-01-01T00:00:00
2026-09-27T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/320", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "solved" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
The maintained Erdős Problems source lists problem 320 as “solved” on 2026-09-27. No Lean verification is inferred from the existence of a formalized statement. **What remains.** No unresolved part of the stated question is identified in the cited result.
[ { "url": "https://www.erdosproblems.com/320", "label": "Erdős Problems #320: solved" }, { "url": "https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml", "label": "Erdős Problems machine-readable status list (snapshot checked 2026-09-27)" }, { "url": "https://huggingface.c...
2026-09-27T00:00:00
Erdős Problems #320: solved: https://www.erdosproblems.com/320 Erdős Problems machine-readable status list (snapshot checked 2026-09-27): https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml
https://www.erdosproblems.com/320
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,047
EP-321
Erdős Problem #321
What is the size of the largest $A\subseteq \{1,\ldots,N\}$ such that all sums $\sum_{n\in S}\frac{1}{n}$ are distinct for $S\subseteq A$?
Erdős Problems (#321, https://www.erdosproblems.com/321). Maintainer status: SOLVED. OEIS: A384927, A391592. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.321).
1
solved
null
null
2
8
0
0
2024-01-01T00:00:00
2026-09-27T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/321", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "solved" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
The maintained Erdős Problems source lists problem 321 as “solved” on 2026-09-27. No Lean verification is inferred from the existence of a formalized statement. **What remains.** No unresolved part of the stated question is identified in the cited result.
[ { "url": "https://www.erdosproblems.com/321", "label": "Erdős Problems #321: solved" }, { "url": "https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml", "label": "Erdős Problems machine-readable status list (snapshot checked 2026-09-27)" }, { "url": "https://huggingface.c...
2026-09-27T00:00:00
Erdős Problems #321: solved: https://www.erdosproblems.com/321 Erdős Problems machine-readable status list (snapshot checked 2026-09-27): https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml
https://www.erdosproblems.com/321
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,048
EP-322
Erdős Problem #322
Let $k\geq 3$ and $A\subset \mathbb{N}$ be the set of $k$th powers. What is the order of growth of $1_A^{(k)}(n)$, i.e. the number of representations of $n$ as the sum of $k$ many $k$th powers? Does there exist some $c>0$ and infinitely many $n$ such that\[1_A^{(k)}(n) >n^c?\]
Erdős Problems (#322, https://www.erdosproblems.com/322). Maintainer status: OPEN. OEIS: A025456, A025418. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.322).
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/322", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "powers" ]
null
null
null
null
https://www.erdosproblems.com/322
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,049
EP-323
Erdős Problem #323
Let $1\leq m\leq k$ and $f_{k,m}(x)$ denote the number of integers $\leq x$ which are the sum of $m$ many nonnegative $k$th powers. Is it true that\[f_{k,k}(x) \gg_\epsilon x^{1-\epsilon}\]for all $\epsilon>0$? Is it true that if $m<k$ then\[f_{k,m}(x) \gg x^{m/k}\]for sufficiently large $x$?
Erdős Problems (#323, https://www.erdosproblems.com/323). Maintainer status: OPEN. OEIS: A004825, A004831, A004832, A004833, A004842, A004843, A004844, A004845, A004857, A004869. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.323).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/323", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "powers" ]
null
null
null
null
https://www.erdosproblems.com/323
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,050
EP-324
Erdős Problem #324
Does there exist a polynomial $f(x)\in\mathbb{Z}[x]$ such that all the sums $f(a)+f(b)$ with $a<b$ nonnegative integers are distinct?
Erdős Problems (#324, https://www.erdosproblems.com/324). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.324).
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/324", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "powers", "sidon-sets" ]
null
null
null
null
https://www.erdosproblems.com/324
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,051
EP-325
Erdős Problem #325
Let $k\geq 3$ and $f_{k,3}(x)$ denote the number of integers $\leq x$ which are the sum of three nonnegative $k$th powers. Is it true that\[f_{k,3}(x) \gg x^{3/k}\]or even $\gg_\epsilon x^{3/k-\epsilon}$?
Erdős Problems (#325, https://www.erdosproblems.com/325). Maintainer status: OPEN. OEIS: A004825, A004832, A004843, A004854, A004865. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.325).
1
partially_solved
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/325", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "powers" ]
null
null
null
null
https://www.erdosproblems.com/325
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,052
EP-326
Erdős Problem #326
Does there exist $A=\{a_1<a_2<\cdots\}\subset \mathbb{N}$ which is a minimal basis of order $2$ (i.e. every large integer is the sum of $2$ elements from $A$, and no proper subset of $A$ has this property), such that\[\lim_{k\to \infty}\frac{a_k}{k^2}=c\]for some $c\neq 0$?
Erdős Problems (#326, https://www.erdosproblems.com/326). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.326).
1
partially_solved
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/326", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "additive-basis" ]
null
null
null
null
https://www.erdosproblems.com/326
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,053
EP-327
Erdős Problem #327
Suppose $A\subseteq \{1,\ldots,N\}$ is such that if $a,b\in A$ and $a\neq b$ then $a+b\nmid ab$. Can $A$ be 'substantially more' than the odd numbers? What if $a,b\in A$ with $a\neq b$ implies $a+b\nmid 2ab$? Must $\lvert A\rvert=o(N)$?
Erdős Problems (#327, https://www.erdosproblems.com/327). Maintainer status: OPEN. OEIS: A384927.
1
open
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/327", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/327
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,054
EP-329
Erdős Problem #329
Suppose $A\subseteq \mathbb{N}$ is a Sidon set. How large can\[\limsup_{N\to \infty}\frac{\lvert A\cap \{1,\ldots,N\}\rvert}{N^{1/2}}\]be?
Erdős Problems (#329, https://www.erdosproblems.com/329). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.329).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/329", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "sidon-sets" ]
null
null
null
null
https://www.erdosproblems.com/329
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,055
EP-330
Erdős Problem #330
Does there exist a minimal basis with positive density, say $A\subset\mathbb{N}$, such that for any $n\in A$ the (upper) density of integers which cannot be represented without using $n$ is positive?
Erdős Problems (#330, https://www.erdosproblems.com/330). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.330).
1
solved
null
null
1
8
0
0
2024-01-01T00:00:00
2026-09-27T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/330", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "additive-basis" ]
The maintained Erdős Problems source lists problem 330 as “proved (Lean)” on 2026-09-27. The source marks a Lean verification of the resolution. **What remains.** No unresolved part of the stated question is identified in the cited result.
[ { "url": "https://www.erdosproblems.com/330", "label": "Erdős Problems #330: proved (Lean)" }, { "url": "https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml", "label": "Erdős Problems machine-readable status list (snapshot checked 2026-09-27)" }, { "url": "https://huggin...
2026-09-27T00:00:00
Erdős Problems #330: proved (Lean): https://www.erdosproblems.com/330 Erdős Problems machine-readable status list (snapshot checked 2026-09-27): https://github.com/teorth/erdosproblems/blob/main/data/problems.yaml
https://www.erdosproblems.com/330
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,056
EP-332
Erdős Problem #332
Let $A\subseteq \mathbb{N}$ and $D(A)$ be the set of those numbers which occur infinitely often as $a_1-a_2$ with $a_1,a_2\in A$. What conditions on $A$ are sufficient to ensure $D(A)$ has bounded gaps?
Erdős Problems (#332, https://www.erdosproblems.com/332). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.332).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/332", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory" ]
null
null
null
null
https://www.erdosproblems.com/332
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,057
EP-334
Erdős Problem #334
Find the best function $f(n)$ such that every $n$ can be written as $n=a+b$ where both $a,b$ are $f(n)$-smooth (that is, are not divisible by any prime $p>f(n)$.)
Erdős Problems (#334, https://www.erdosproblems.com/334). Maintainer status: OPEN. OEIS: A062241, A045535.
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/334", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory" ]
null
null
null
null
https://www.erdosproblems.com/334
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,058
EP-335
Erdős Problem #335
Let $d(A)$ denote the density of $A\subseteq \mathbb{N}$. Characterise those $A,B\subseteq \mathbb{N}$ with positive density such that\[d(A+B)=d(A)+d(B).\]
Erdős Problems (#335, https://www.erdosproblems.com/335). Maintainer status: OPEN.
1
partially_solved
null
null
2
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/335", "checked_at": "2026-10-16", "kind": "partial", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "additive-combinatorics" ]
null
null
null
null
https://www.erdosproblems.com/335
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,059
EP-336
Erdős Problem #336
For $r\geq 2$ let $h(r)$ be the maximal finite $k$ such that there exists a basis $A\subseteq \mathbb{N}$ of order $r$ (so every large integer is the sum of at most $r$ integers from $A$) and exact order $k$ (so every large integer is the sum of exactly $k$ integers from $A$). Find the value of\[\lim_r \frac{h(r)}{r^2...
Erdős Problems (#336, https://www.erdosproblems.com/336). Maintainer status: OPEN.
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/336", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "additive-basis" ]
null
null
null
null
https://www.erdosproblems.com/336
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,060
EP-338
Erdős Problem #338
The restricted order of a basis is the least integer $t$ (if it exists) such that every large integer is the sum of at most $t$ distinct summands from $A$. What are necessary and sufficient conditions that this exists? Can it be bounded (when it exists) in terms of the order of the basis? What are necessary and suffici...
Erdős Problems (#338, https://www.erdosproblems.com/338). Maintainer status: OPEN.
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/338", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "additive-basis" ]
null
null
null
null
https://www.erdosproblems.com/338
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,061
EP-340
Erdős Problem #340
Let $A=\{1,2,4,8,13,21,31,45,66,81,97,\ldots\}$ be the greedy Sidon sequence: we begin with $1$ and iteratively include the next smallest integer that preserves the Sidon property (i.e. there are no non-trivial solutions to $a+b=c+d$). What is the order of growth of $A$? Is it true that\[\lvert A\cap \{1,\ldots,N\}\rve...
Erdős Problems (#340, https://www.erdosproblems.com/340). Maintainer status: OPEN. OEIS: A080200, A005282. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.340).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/340", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory", "additive-combinatorics", "sidon-sets" ]
null
null
null
null
https://www.erdosproblems.com/340
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,062
EP-341
Erdős Problem #341
Let $A=\{a_1<\cdots<a_k\}$ be a finite set of positive integers and extend it to an infinite sequence $\overline{A}=\{a_1<a_2<\cdots \}$ by defining $a_{n+1}$ for $n\geq k$ to be the least integer exceeding $a_n$ which is not of the form $a_i+a_j$ with $i,j\leq n$. Is it true that the sequence of differences $a_{m+1}-a...
Erdős Problems (#341, https://www.erdosproblems.com/341). Maintainer status: OPEN. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.341).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/341", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory" ]
null
null
null
null
https://www.erdosproblems.com/341
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
2,063
EP-342
Erdős Problem #342
With $a_1=1$ and $a_2=2$ let $a_{n+1}$ for $n\geq 2$ be the least integer $>a_n$ which can be expressed uniquely as $a_i+a_j$ for $i<j\leq n$. What can be said about this sequence? Do infinitely many pairs $a,a+2$ occur? Does this sequence eventually have periodic differences? Is the density $0$?
Erdős Problems (#342, https://www.erdosproblems.com/342). Maintainer status: OPEN. OEIS: A002858. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.342).
1
open
null
null
1
8
0
0
2024-01-01T00:00:00
2024-01-01T00:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 1, "level": 1, "name": "L1: Tractable", "description": "Problems that may be within reach with current techniques. Reserved for future additions.", "color_class": "text-green-600 bg-green-50 border-green-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/342", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "number-theory" ]
null
null
null
null
https://www.erdosproblems.com/342
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null