sequence_id
stringlengths 7
7
| sequence_name
stringlengths 4
573
| sequence
listlengths 1
348
| keywords
listlengths 1
8
| score
int64 1
2.35k
| offset_a
int64 -14,827
666,262,453B
| offset_b
int64 0
635M
⌀ | cross_references
listlengths 1
128
⌀ | former_ids
listlengths 1
3
⌀ | author
stringlengths 7
231
⌀ | timestamp
timestamp[us]date 1999-12-11 03:00:00
2025-07-19 00:40:46
| filename
stringlengths 29
29
| hash
stringlengths 32
32
|
|---|---|---|---|---|---|---|---|---|---|---|---|---|
A004001
|
Hofstadter-Conway $10000 sequence: a(n) = a(a(n-1)) + a(n-a(n-1)) with a(1) = a(2) = 1.
|
[
"1",
"1",
"2",
"2",
"3",
"4",
"4",
"4",
"5",
"6",
"7",
"7",
"8",
"8",
"8",
"8",
"9",
"10",
"11",
"12",
"12",
"13",
"14",
"14",
"15",
"15",
"15",
"16",
"16",
"16",
"16",
"16",
"17",
"18",
"19",
"20",
"21",
"21",
"22",
"23",
"24",
"24",
"25",
"26",
"26",
"27",
"27",
"27",
"28",
"29",
"29",
"30",
"30",
"30",
"31",
"31",
"31",
"31",
"32",
"32",
"32",
"32",
"32",
"32",
"33",
"34",
"35",
"36",
"37",
"38",
"38",
"39",
"40",
"41",
"42"
] |
[
"nonn",
"easy",
"nice"
] | 186
| 1
| 3
|
[
"A004001",
"A004074",
"A005185",
"A005229",
"A005350",
"A005707",
"A051135",
"A055748",
"A080677",
"A086841",
"A087686",
"A088359",
"A093878",
"A093879",
"A188163",
"A249071",
"A265332",
"A265901",
"A265903",
"A266341",
"A267111",
"A267112"
] |
[
"M0276"
] |
N. J. A. Sloane
| 2025-02-16T08:32:27
|
oeisdata/seq/A004/A004001.seq
|
d8d0d7b8da23519b7351095144718aa7
|
A004002
|
Benford numbers: a(n) = e^e^...^e (n times) rounded to nearest integer.
|
[
"1",
"3",
"15",
"3814279"
] |
[
"nonn"
] | 35
| 0
| 2
|
[
"A004002",
"A056072",
"A073236",
"A225053"
] |
[
"M3010"
] |
N. J. A. Sloane
| 2024-07-20T19:46:06
|
oeisdata/seq/A004/A004002.seq
|
00864e7d9a611be3470e6bc785f0bee8
|
A004003
|
Number of domino tilings (or dimer coverings) of a 2n X 2n square.
|
[
"1",
"2",
"36",
"6728",
"12988816",
"258584046368",
"53060477521960000",
"112202208776036178000000",
"2444888770250892795802079170816",
"548943583215388338077567813208427340288",
"1269984011256235834242602753102293934298576249856"
] |
[
"nonn",
"easy",
"nice"
] | 144
| 0
| 2
|
[
"A004003",
"A006125",
"A006253",
"A028420",
"A065072",
"A099390",
"A124997",
"A187596",
"A239273",
"A256043"
] |
[
"M2160"
] |
N. J. A. Sloane, Greg Huber
| 2025-02-16T08:32:27
|
oeisdata/seq/A004/A004003.seq
|
11a0eacbe04bc95cd5939fb858c76d93
|
A004004
|
a(n) = (3^(2*n+1) - 8*n - 3)/16.
|
[
"0",
"1",
"14",
"135",
"1228",
"11069",
"99642",
"896803",
"8071256",
"72641337",
"653772070",
"5883948671",
"52955538084",
"476599842805",
"4289398585298",
"38604587267739",
"347441285409712",
"3126971568687473",
"28142744118187326",
"253284697063686007",
"2279562273573174140",
"20516060462158567341"
] |
[
"nonn",
"easy"
] | 48
| 0
| 3
|
[
"A004004",
"A162005",
"A162008",
"A162009",
"A162010",
"A162011",
"A162014"
] |
[
"M4943"
] |
N. J. A. Sloane, Simon Plouffe
| 2025-02-08T15:32:15
|
oeisdata/seq/A004/A004004.seq
|
7a4892ec22e2be190f6f9bfbd17d37af
|
A004005
|
Coefficients of elliptic function sn.
|
[
"1",
"135",
"5478",
"165826",
"4494351",
"116294673",
"2949965020",
"74197080276",
"1859539731885",
"46535238000235",
"1163848723925346",
"29100851707716150",
"727566807977891803",
"18189614152200873621",
"454744658216502193656"
] |
[
"nonn",
"nice",
"easy"
] | 45
| 2
| 2
|
[
"A004005",
"A060628"
] |
[
"M5397"
] |
N. J. A. Sloane, Simon Plouffe
| 2022-04-13T13:25:17
|
oeisdata/seq/A004/A004005.seq
|
a5eaa0c8996713f02d461881049496e1
|
A004006
|
a(n) = C(n,1) + C(n,2) + C(n,3), or n*(n^2 + 5)/6.
|
[
"0",
"1",
"3",
"7",
"14",
"25",
"41",
"63",
"92",
"129",
"175",
"231",
"298",
"377",
"469",
"575",
"696",
"833",
"987",
"1159",
"1350",
"1561",
"1793",
"2047",
"2324",
"2625",
"2951",
"3303",
"3682",
"4089",
"4525",
"4991",
"5488",
"6017",
"6579",
"7175",
"7806",
"8473",
"9177",
"9919",
"10700",
"11521",
"12383",
"13287",
"14234",
"15225"
] |
[
"nonn",
"nice",
"easy"
] | 176
| 0
| 3
|
[
"A000124",
"A000217",
"A000292",
"A000447",
"A000578",
"A001477",
"A004006",
"A004068",
"A004126",
"A004188",
"A004466",
"A004467",
"A005900",
"A006003",
"A006527",
"A006552",
"A007310",
"A007588",
"A051576",
"A055795",
"A062025",
"A063521",
"A063522",
"A063523",
"A128834",
"A144329",
"A228074"
] | null |
Albert D. Rich (AlbertRich(AT)msn.com)
| 2025-06-19T00:14:16
|
oeisdata/seq/A004/A004006.seq
|
d84e68ab7151622f9a8334eebb0a2a1b
|
A004007
|
Theta series of E_6 lattice.
|
[
"1",
"72",
"270",
"720",
"936",
"2160",
"2214",
"3600",
"4590",
"6552",
"5184",
"10800",
"9360",
"12240",
"13500",
"17712",
"14760",
"25920",
"19710",
"26064",
"28080",
"36000",
"25920",
"47520",
"37638",
"43272",
"45900",
"59040",
"46800",
"75600",
"51840",
"69264",
"73710",
"88560",
"62208",
"108000",
"85176"
] |
[
"nonn"
] | 29
| 0
| 2
|
[
"A004007",
"A005129"
] |
[
"M5349"
] |
N. J. A. Sloane
| 2018-01-11T01:09:04
|
oeisdata/seq/A004/A004007.seq
|
ea15484d7703c806722f5889dd0a5e02
|
A004008
|
Expansion of theta series of E_7 lattice in powers of q^2.
|
[
"1",
"126",
"756",
"2072",
"4158",
"7560",
"11592",
"16704",
"24948",
"31878",
"39816",
"55944",
"66584",
"76104",
"99792",
"116928",
"133182",
"160272",
"177660",
"205128",
"249480",
"265104",
"281736",
"350784",
"382536",
"390726",
"470232",
"505568",
"532800",
"615384",
"640080",
"701568",
"799092",
"809424",
"853776"
] |
[
"nonn",
"easy"
] | 29
| 0
| 2
|
[
"A003781",
"A004008",
"A005875",
"A228746"
] |
[
"M5388"
] |
N. J. A. Sloane
| 2025-02-16T08:32:27
|
oeisdata/seq/A004/A004008.seq
|
c9d071be9f10fa5aaf2bc5d2a1acc89d
|
A004009
|
Expansion of Eisenstein series E_4(q) (alternate convention E_2(q)); theta series of E_8 lattice.
|
[
"1",
"240",
"2160",
"6720",
"17520",
"30240",
"60480",
"82560",
"140400",
"181680",
"272160",
"319680",
"490560",
"527520",
"743040",
"846720",
"1123440",
"1179360",
"1635120",
"1646400",
"2207520",
"2311680",
"2877120",
"2920320",
"3931200",
"3780240",
"4747680",
"4905600",
"6026880"
] |
[
"nonn",
"easy",
"nice"
] | 168
| 0
| 2
|
[
"A000143",
"A001158",
"A004009",
"A006352",
"A007331",
"A008410",
"A008411",
"A013973",
"A013974",
"A029828",
"A029829",
"A029830",
"A029831",
"A035016",
"A046948",
"A058550",
"A108091"
] |
[
"M5416"
] |
N. J. A. Sloane
| 2025-02-16T08:32:27
|
oeisdata/seq/A004/A004009.seq
|
cdad89efeade98eae7851e1d31b76ea3
|
A004010
|
Theta series of 12-dimensional Coxeter-Todd lattice K_12.
|
[
"1",
"0",
"756",
"4032",
"20412",
"60480",
"139860",
"326592",
"652428",
"1020096",
"2000376",
"3132864",
"4445532",
"7185024",
"10747296",
"13148352",
"21003948",
"27506304",
"33724404",
"48009024",
"64049832",
"70709184",
"102958128",
"124782336",
"142254252",
"189423360",
"237588120",
"248250240",
"344391264"
] |
[
"easy",
"nonn",
"nice"
] | 39
| 0
| 3
|
[
"A004010",
"A004046",
"A008657",
"A107658"
] |
[
"M5478"
] |
N. J. A. Sloane
| 2025-02-16T08:32:27
|
oeisdata/seq/A004/A004010.seq
|
b175d63b431930340e9bc0f1dbcfc003
|
A004011
|
Theta series of D_4 lattice; Fourier coefficients of Eisenstein series E_{gamma,2}.
|
[
"1",
"24",
"24",
"96",
"24",
"144",
"96",
"192",
"24",
"312",
"144",
"288",
"96",
"336",
"192",
"576",
"24",
"432",
"312",
"480",
"144",
"768",
"288",
"576",
"96",
"744",
"336",
"960",
"192",
"720",
"576",
"768",
"24",
"1152",
"432",
"1152",
"312",
"912",
"480",
"1344",
"144",
"1008",
"768",
"1056",
"288",
"1872",
"576",
"1152",
"96",
"1368",
"744",
"1728",
"336"
] |
[
"nonn",
"easy",
"core",
"nice"
] | 145
| 0
| 2
|
[
"A000118",
"A000593",
"A002388",
"A004011",
"A004016",
"A005882",
"A005928",
"A008658",
"A046949",
"A096727",
"A108092",
"A108096"
] |
[
"M5140"
] |
N. J. A. Sloane
| 2025-07-02T16:01:54
|
oeisdata/seq/A004/A004011.seq
|
dc817f4d329f4916fe54f3e66a41e31f
|
A004012
|
Theta series of hexagonal close-packing.
|
[
"1",
"0",
"0",
"12",
"0",
"0",
"6",
"0",
"2",
"18",
"0",
"12",
"6",
"0",
"0",
"12",
"0",
"12",
"6",
"6",
"12",
"24",
"6",
"0",
"0",
"12",
"0",
"12",
"0",
"24",
"12",
"12",
"2",
"12",
"6",
"24",
"6",
"12",
"0",
"24",
"0",
"12",
"0",
"6",
"24",
"12",
"12",
"24",
"6",
"12",
"0",
"24",
"0",
"24",
"18",
"12",
"12",
"24",
"0",
"12",
"0",
"12",
"0",
"36",
"0",
"24",
"12",
"18",
"12",
"24",
"12",
"48",
"2",
"0",
"0",
"36",
"0",
"0",
"24",
"12",
"12"
] |
[
"nonn",
"easy",
"nice"
] | 27
| 0
| 4
| null |
[
"M4817"
] |
N. J. A. Sloane
| 2025-02-16T08:32:28
|
oeisdata/seq/A004/A004012.seq
|
3dda759f67324fa2afc988d6cbf51260
|
A004013
|
Theta series of body-centered cubic (b.c.c.) lattice.
|
[
"1",
"0",
"0",
"8",
"6",
"0",
"0",
"0",
"12",
"0",
"0",
"24",
"8",
"0",
"0",
"0",
"6",
"0",
"0",
"24",
"24",
"0",
"0",
"0",
"24",
"0",
"0",
"32",
"0",
"0",
"0",
"0",
"12",
"0",
"0",
"48",
"30",
"0",
"0",
"0",
"24",
"0",
"0",
"24",
"24",
"0",
"0",
"0",
"8",
"0",
"0",
"48",
"24",
"0",
"0",
"0",
"48",
"0",
"0",
"72",
"0",
"0",
"0",
"0",
"6",
"0",
"0",
"24",
"48",
"0",
"0",
"0",
"36",
"0",
"0",
"56",
"24",
"0",
"0",
"0",
"24",
"0",
"0",
"72",
"48",
"0",
"0",
"0",
"24",
"0",
"0"
] |
[
"nonn",
"easy",
"nice"
] | 58
| 0
| 4
|
[
"A004011",
"A004013",
"A004014",
"A004015",
"A005875",
"A008422",
"A008423",
"A008424",
"A008425",
"A008426",
"A008427",
"A008443",
"A023916",
"A023936",
"A045826",
"A045828",
"A045834",
"A213056"
] |
[
"M4473"
] |
N. J. A. Sloane
| 2025-02-16T08:32:28
|
oeisdata/seq/A004/A004013.seq
|
0be917e60a80d65fc0992fca2342560d
|
A004014
|
Norms of vectors in the b.c.c. lattice.
|
[
"0",
"3",
"4",
"8",
"11",
"12",
"16",
"19",
"20",
"24",
"27",
"32",
"35",
"36",
"40",
"43",
"44",
"48",
"51",
"52",
"56",
"59",
"64",
"67",
"68",
"72",
"75",
"76",
"80",
"83",
"84",
"88",
"91",
"96",
"99",
"100",
"104",
"107",
"108",
"115",
"116",
"120",
"123",
"128",
"131",
"132",
"136",
"139",
"140",
"144",
"147",
"148",
"152",
"155",
"160",
"163",
"164",
"168"
] |
[
"nonn",
"nice",
"easy"
] | 43
| 0
| 2
|
[
"A004013",
"A004014",
"A004215",
"A017101",
"A034045",
"A047458"
] |
[
"M2347"
] |
N. J. A. Sloane
| 2022-11-07T07:41:40
|
oeisdata/seq/A004/A004014.seq
|
ad82a1e1cce2c914065362acf84e469f
|
A004015
|
Theta series of face-centered cubic (f.c.c.) lattice.
|
[
"1",
"12",
"6",
"24",
"12",
"24",
"8",
"48",
"6",
"36",
"24",
"24",
"24",
"72",
"0",
"48",
"12",
"48",
"30",
"72",
"24",
"48",
"24",
"48",
"8",
"84",
"24",
"96",
"48",
"24",
"0",
"96",
"6",
"96",
"48",
"48",
"36",
"120",
"24",
"48",
"24",
"48",
"48",
"120",
"24",
"120",
"0",
"96",
"24",
"108",
"30",
"48",
"72",
"72",
"32",
"144",
"0",
"96",
"72",
"72",
"48",
"120",
"0",
"144",
"12",
"48",
"48",
"168",
"48",
"96"
] |
[
"nonn",
"easy",
"nice"
] | 68
| 0
| 2
|
[
"A000007",
"A000122",
"A004013",
"A004015",
"A004016",
"A005875",
"A005901",
"A008444",
"A008445",
"A008446",
"A008447",
"A008448",
"A008449",
"A045828",
"A055039"
] |
[
"M4821"
] |
N. J. A. Sloane
| 2025-02-24T18:04:25
|
oeisdata/seq/A004/A004015.seq
|
11f064f725eea8f1e3942649ee88d804
|
A004016
|
Theta series of planar hexagonal lattice A_2.
|
[
"1",
"6",
"0",
"6",
"6",
"0",
"0",
"12",
"0",
"6",
"0",
"0",
"6",
"12",
"0",
"0",
"6",
"0",
"0",
"12",
"0",
"12",
"0",
"0",
"0",
"6",
"0",
"6",
"12",
"0",
"0",
"12",
"0",
"0",
"0",
"0",
"6",
"12",
"0",
"12",
"0",
"0",
"0",
"12",
"0",
"0",
"0",
"0",
"6",
"18",
"0",
"0",
"12",
"0",
"0",
"0",
"0",
"12",
"0",
"0",
"0",
"12",
"0",
"12",
"6",
"0",
"0",
"12",
"0",
"0",
"0",
"0",
"0",
"12",
"0",
"6",
"12",
"0",
"0",
"12",
"0"
] |
[
"nonn",
"nice",
"easy"
] | 139
| 0
| 2
|
[
"A000007",
"A000122",
"A002324",
"A003051",
"A003215",
"A004015",
"A004016",
"A005881",
"A005882",
"A005928",
"A008444",
"A008445",
"A008446",
"A008447",
"A008448",
"A008449",
"A008458",
"A033685",
"A033687",
"A035019",
"A038587",
"A038591",
"A186706"
] |
[
"M4042"
] |
N. J. A. Sloane
| 2025-02-16T08:32:28
|
oeisdata/seq/A004/A004016.seq
|
ad1ce85b576485b5231c233c71bc9a1c
|
A004017
|
Theta series of E_8 lattice with respect to deep hole.
|
[
"16",
"128",
"448",
"1024",
"2016",
"3584",
"5504",
"8192",
"12112",
"16128",
"21312",
"28672",
"35168",
"44032",
"56448",
"65536",
"78624",
"96896",
"109760",
"129024",
"154112",
"170496",
"194688",
"229376",
"252016",
"281344",
"327040",
"352256",
"390240",
"451584",
"476672",
"524288",
"596736",
"628992"
] |
[
"nonn",
"easy"
] | 23
| 1
| 1
|
[
"A004017",
"A007331"
] |
[
"M5009"
] |
N. J. A. Sloane
| 2024-10-14T12:22:44
|
oeisdata/seq/A004/A004017.seq
|
7e973f3b90c98072fe5c7e700d89fb3c
|
A004018
|
Theta series of square lattice (or number of ways of writing n as a sum of 2 squares). Often denoted by r(n) or r_2(n).
|
[
"1",
"4",
"4",
"0",
"4",
"8",
"0",
"0",
"4",
"4",
"8",
"0",
"0",
"8",
"0",
"0",
"4",
"8",
"4",
"0",
"8",
"0",
"0",
"0",
"0",
"12",
"8",
"0",
"0",
"8",
"0",
"0",
"4",
"0",
"8",
"0",
"4",
"8",
"0",
"0",
"8",
"8",
"0",
"0",
"0",
"8",
"0",
"0",
"0",
"4",
"12",
"0",
"8",
"8",
"0",
"0",
"0",
"0",
"8",
"0",
"0",
"8",
"0",
"0",
"4",
"16",
"0",
"0",
"8",
"0",
"0",
"0",
"4",
"8",
"8",
"0",
"0",
"0",
"0",
"0",
"8",
"4",
"8",
"0",
"0",
"16",
"0",
"0",
"0",
"8",
"8",
"0",
"0",
"0",
"0",
"0",
"0",
"8",
"4",
"0",
"12",
"8"
] |
[
"nonn",
"easy",
"nice",
"core"
] | 243
| 0
| 2
|
[
"A001481",
"A002654",
"A004018",
"A004020",
"A005883",
"A014198",
"A057655",
"A057961",
"A057962",
"A071383",
"A071385",
"A104271",
"A105673",
"A122141",
"A286815",
"A319574"
] |
[
"M3218"
] |
N. J. A. Sloane
| 2025-05-18T16:37:09
|
oeisdata/seq/A004/A004018.seq
|
dda24ab3c745cf7f0743299c068e4998
|
A004019
|
a(0) = 0; for n > 0, a(n) = (a(n-1) + 1)^2.
|
[
"0",
"1",
"4",
"25",
"676",
"458329",
"210066388900",
"44127887745906175987801",
"1947270476915296449559703445493848930452791204",
"3791862310265926082868235028027893277370233152247388584761734150717768254410341175325352025"
] |
[
"nonn",
"easy",
"nice"
] | 105
| 0
| 3
|
[
"A000290",
"A001699",
"A003095",
"A004019",
"A056207",
"A091980",
"A355108"
] |
[
"M3611"
] |
N. J. A. Sloane
| 2025-01-16T11:30:20
|
oeisdata/seq/A004/A004019.seq
|
5cf8feff7845eacfeb6539b11795729a
|
A004020
|
Theta series of square lattice with respect to edge.
|
[
"2",
"4",
"2",
"4",
"4",
"0",
"6",
"4",
"0",
"4",
"4",
"4",
"2",
"4",
"0",
"4",
"8",
"0",
"4",
"0",
"2",
"8",
"4",
"0",
"4",
"4",
"0",
"4",
"4",
"4",
"2",
"8",
"0",
"0",
"4",
"0",
"8",
"4",
"4",
"4",
"0",
"0",
"6",
"4",
"0",
"4",
"8",
"0",
"4",
"4",
"0",
"8",
"0",
"0",
"0",
"8",
"6",
"4",
"4",
"0",
"4",
"4",
"0",
"0",
"4",
"4",
"8",
"4",
"0",
"4",
"4",
"0",
"6",
"4",
"0",
"0",
"8",
"0",
"4",
"4",
"0",
"12",
"0",
"4",
"4",
"0",
"0",
"4",
"4",
"0",
"2",
"8",
"4",
"4",
"8",
"0",
"0",
"4",
"0",
"4",
"4",
"4",
"4",
"0"
] |
[
"nonn"
] | 35
| 0
| 1
|
[
"A000122",
"A000700",
"A000796",
"A004020",
"A004531",
"A008441",
"A010054",
"A121373"
] |
[
"M0931"
] |
N. J. A. Sloane
| 2025-02-16T08:32:28
|
oeisdata/seq/A004/A004020.seq
|
0b5444aca99fe8699f6898cafd8a77fb
|
A004021
|
Theta series of packing P_{10c}.
|
[
"1",
"372",
"768",
"5684",
"6144",
"28608",
"23040",
"91956",
"61440",
"224680",
"140544",
"458688",
"276480",
"358240",
"480768",
"1467188",
"798720",
"2329012",
"1251072",
"3590952",
"1843200"
] |
[
"nonn"
] | 11
| 0
| 2
| null |
[
"M5448"
] |
N. J. A. Sloane
| 2023-10-24T06:09:16
|
oeisdata/seq/A004/A004021.seq
|
ecaceeb28ea43f5908f5dc960497f1ad
|
A004022
|
Primes of the form (10^k - 1)/9. Also called repunit primes or repdigit primes.
|
[
"11",
"1111111111111111111",
"11111111111111111111111"
] |
[
"nonn",
"nice",
"bref",
"changed"
] | 99
| 1
| 1
|
[
"A004022",
"A004023",
"A020449",
"A046413",
"A116692"
] |
[
"M4816"
] |
N. J. A. Sloane
| 2025-07-16T10:04:41
|
oeisdata/seq/A004/A004022.seq
|
7a4cfa6a1c4d0f071d49553fdeaacd0c
|
A004023
|
Indices of prime repunits: numbers k such that 11...111 (with k 1's) = (10^k - 1)/9 is prime.
|
[
"2",
"19",
"23",
"317",
"1031",
"49081",
"86453",
"109297",
"270343",
"5794777",
"8177207"
] |
[
"hard",
"nonn",
"nice",
"more"
] | 279
| 1
| 1
|
[
"A002275",
"A004022",
"A004023",
"A055557",
"A085104"
] |
[
"M2114"
] |
N. J. A. Sloane
| 2025-04-25T04:27:28
|
oeisdata/seq/A004/A004023.seq
|
7bb6c76af2ff8533d030be0729bf2353
|
A004024
|
Theta series of b.c.c. lattice with respect to deep hole.
|
[
"4",
"4",
"8",
"12",
"4",
"12",
"12",
"12",
"16",
"16",
"8",
"8",
"28",
"12",
"20",
"24",
"8",
"16",
"28",
"12",
"16",
"28",
"20",
"32",
"20",
"16",
"16",
"32",
"20",
"24",
"28",
"8",
"36",
"44",
"12",
"32",
"36",
"16",
"24",
"20",
"28",
"20",
"56",
"28",
"16",
"40",
"20",
"40",
"44",
"12",
"36",
"40",
"20",
"32",
"40",
"16",
"24",
"60",
"32",
"36",
"40",
"24",
"32",
"60",
"24",
"40",
"24",
"20",
"60",
"36",
"24",
"32",
"56",
"32"
] |
[
"nonn",
"easy",
"nice"
] | 33
| 0
| 1
|
[
"A004024",
"A045831"
] |
[
"M3227"
] |
N. J. A. Sloane
| 2017-07-07T03:45:09
|
oeisdata/seq/A004/A004024.seq
|
27dfd2cf2c426b5f1433860958fef180
|
A004025
|
Theta series of b.c.c. lattice with respect to long edge.
|
[
"2",
"4",
"0",
"0",
"8",
"8",
"0",
"0",
"10",
"8",
"0",
"0",
"8",
"16",
"0",
"0",
"16",
"12",
"0",
"0",
"16",
"8",
"0",
"0",
"10",
"24",
"0",
"0",
"24",
"16",
"0",
"0",
"16",
"16",
"0",
"0",
"8",
"24",
"0",
"0",
"32",
"16",
"0",
"0",
"24",
"16",
"0",
"0",
"18",
"28",
"0",
"0",
"24",
"32",
"0",
"0",
"16",
"8",
"0",
"0",
"24",
"32",
"0",
"0",
"32",
"32",
"0",
"0",
"32",
"16",
"0",
"0",
"16",
"40",
"0",
"0",
"32"
] |
[
"nonn",
"easy"
] | 38
| 1
| 1
|
[
"A004025",
"A045828",
"A045834",
"A045836"
] |
[
"M0928"
] |
N. J. A. Sloane
| 2025-02-16T08:32:28
|
oeisdata/seq/A004/A004025.seq
|
a966a570183d06ba2c306c59fea2371c
|
A004026
|
Number of perfect quadratic forms or lattices in dimension n.
|
[
"1",
"1",
"1",
"2",
"3",
"7",
"33",
"10916"
] |
[
"hard",
"more",
"nonn",
"nice"
] | 44
| 1
| 4
|
[
"A004026",
"A033689",
"A037075",
"A065535",
"A065536",
"A122079",
"A122080"
] |
[
"M0862"
] |
N. J. A. Sloane
| 2021-05-04T12:03:12
|
oeisdata/seq/A004/A004026.seq
|
87b5c75f9ed4632923ac4f962544dc9e
|
A004027
|
Number of arithmetic n-dimensional crystal classes.
|
[
"1",
"2",
"13",
"73",
"710",
"6079",
"85308"
] |
[
"nonn",
"hard",
"nice",
"more"
] | 45
| 0
| 2
|
[
"A004027",
"A004028",
"A004029",
"A006227",
"A307288"
] |
[
"M2060"
] |
N. J. A. Sloane
| 2023-10-06T07:33:02
|
oeisdata/seq/A004/A004027.seq
|
d25c2134036dffce148a421ca17fbec5
|
A004028
|
Number of geometric n-dimensional crystal classes.
|
[
"1",
"2",
"10",
"32",
"227",
"955",
"7103"
] |
[
"nonn",
"hard",
"nice",
"more"
] | 47
| 0
| 2
|
[
"A004027",
"A004028",
"A004029"
] |
[
"M1965"
] |
N. J. A. Sloane
| 2023-09-28T02:02:22
|
oeisdata/seq/A004/A004028.seq
|
82ec9deacfef696bc04b02b8b415eb03
|
A004029
|
Number of n-dimensional space groups.
|
[
"1",
"2",
"17",
"219",
"4783",
"222018",
"28927915"
] |
[
"nonn",
"hard",
"more",
"nice"
] | 62
| 0
| 2
|
[
"A004027",
"A004029",
"A006227",
"A293060"
] |
[
"M2103"
] |
N. J. A. Sloane
| 2023-10-04T22:25:51
|
oeisdata/seq/A004/A004029.seq
|
95311f2c207c0a55e7fdbe8b16fe1db4
|
A004030
|
Erroneous version of A256413.
|
[
"1",
"1",
"5",
"14",
"64",
"189",
"826"
] |
[
"dead"
] | 48
| 0
| 3
|
[
"A004030",
"A256413"
] |
[
"M3847"
] | null | 2017-07-09T04:08:22
|
oeisdata/seq/A004/A004030.seq
|
874b7d73d1e1cbee81d6c1c748c38158
|
A004031
|
Number of n-dimensional crystal systems.
|
[
"1",
"1",
"4",
"7",
"33",
"59",
"251"
] |
[
"nonn",
"hard",
"more",
"nice"
] | 29
| 0
| 3
|
[
"A004026",
"A004029",
"A004031",
"A004032",
"A006226",
"A006227",
"A080738"
] |
[
"M3317"
] |
N. J. A. Sloane
| 2022-05-01T02:25:17
|
oeisdata/seq/A004/A004031.seq
|
5e32ae5208540e61a54c7c6dead5914a
|
A004032
|
Number of n-dimensional crystal families.
|
[
"1",
"1",
"4",
"6",
"23",
"32",
"91"
] |
[
"hard",
"nonn",
"nice"
] | 21
| 0
| 3
|
[
"A004027",
"A004031",
"A004032",
"A006226",
"A006227"
] |
[
"M3289"
] |
N. J. A. Sloane
| 2022-01-31T01:26:44
|
oeisdata/seq/A004/A004032.seq
|
1996cc0f236eb1cc8614bd5f1aa1eae6
|
A004033
|
Theta series of lattice A_2 tensor E_8 (dimension 16, det. 6561, min. norm 4). Also theta series of Eisenstein version of E_8 lattice.
|
[
"1",
"0",
"720",
"13440",
"97200",
"455040",
"1714320",
"4821120",
"12380400",
"29043840",
"58980960",
"114076800",
"219310320",
"367338240",
"621878400",
"1037727360",
"1583679600",
"2401816320",
"3747180240",
"5232470400",
"7551983520",
"10938261120",
"14715224640",
"19930775040",
"28073386800",
"35727920640"
] |
[
"nonn",
"easy"
] | 41
| 0
| 3
|
[
"A004016",
"A004033",
"A007332",
"A037150"
] |
[
"M5472"
] |
N. J. A. Sloane
| 2025-02-16T08:32:28
|
oeisdata/seq/A004/A004033.seq
|
b01d5e5141b9def704881a13da785ac3
|
A004034
|
Theta series of Leech lattice with respect to deep hole of type A_1.
|
[
"48",
"4096",
"97152",
"1130496",
"8400704",
"45785088"
] |
[
"nonn"
] | 13
| 0
| 1
| null |
[
"M5294"
] |
N. J. A. Sloane
| 2023-10-24T06:10:14
|
oeisdata/seq/A004/A004034.seq
|
fce02052cae6b799a11df0ec7132c6b3
|
A004035
|
The coding-theoretic function A(n,4,5).
|
[
"0",
"1",
"1",
"3",
"8",
"18",
"36",
"66",
"80"
] |
[
"nonn",
"hard",
"more"
] | 25
| 4
| 4
| null |
[
"M2729"
] |
N. J. A. Sloane
| 2018-12-14T09:48:11
|
oeisdata/seq/A004/A004035.seq
|
2aaec9bb4021d06fe8ef43163d212db8
|
A004036
|
The coding-theoretic function A(n,4,6).
|
[
"1",
"1",
"4",
"12",
"30",
"66",
"132"
] |
[
"nonn",
"hard",
"more"
] | 23
| 6
| 3
| null |
[
"M3438"
] |
N. J. A. Sloane
| 2025-06-16T15:52:12
|
oeisdata/seq/A004/A004036.seq
|
4054ce72fa437c0b6d4d9a5fb8f25f1d
|
A004037
|
The coding-theoretic function A(n,6,4).
|
[
"1",
"1",
"1",
"2",
"2",
"3",
"5",
"6",
"9",
"13",
"14",
"15",
"20",
"20",
"22",
"25",
"30",
"31",
"37",
"40",
"42",
"50",
"52",
"54",
"63",
"65",
"67",
"76",
"80",
"82",
"92",
"96",
"99",
"111",
"114",
"117",
"130",
"133",
"136",
"149",
"154",
"157",
"171",
"176",
"180",
"196",
"200",
"204",
"221",
"225",
"229",
"246",
"252",
"256",
"274",
"280",
"285",
"305",
"310",
"315",
"336"
] |
[
"nonn"
] | 48
| 4
| 4
| null |
[
"M0291",
"N0104"
] |
N. J. A. Sloane
| 2024-02-27T09:53:24
|
oeisdata/seq/A004/A004037.seq
|
a9b929405b6afc9616ac0bd1c63d8a27
|
A004038
|
The coding-theoretic function A(n,6,5).
|
[
"1",
"1",
"2",
"3",
"6",
"11",
"12",
"18",
"28",
"42",
"48",
"68"
] |
[
"nonn",
"hard",
"more"
] | 19
| 6
| 3
| null |
[
"M0779"
] |
N. J. A. Sloane
| 2025-06-16T15:52:27
|
oeisdata/seq/A004/A004038.seq
|
5a49989872568425aed58ba0c5b525e2
|
A004039
|
The coding-theoretic function A(n,6,6).
|
[
"1",
"1",
"1",
"3",
"5",
"11",
"22",
"26",
"42",
"70",
"112"
] |
[
"nonn",
"hard",
"more"
] | 19
| 6
| 4
| null |
[
"M2483"
] |
N. J. A. Sloane
| 2025-06-16T15:58:20
|
oeisdata/seq/A004/A004039.seq
|
025fdb1748d941d46bcb4012e16abae0
|
A004040
|
Inversion of A000257.
|
[
"1",
"2",
"6",
"23",
"103",
"512",
"2740",
"15485",
"91245",
"555662",
"3475090",
"22214707",
"144640291",
"956560748",
"6411521056",
"43478151737",
"297864793993",
"2059159989914",
"14350039389022",
"100726680316559",
"711630547589023",
"5057282786190872",
"36132861123763276",
"259423620328055093",
"1870954187618001253"
] |
[
"nonn"
] | 13
| 0
| 2
|
[
"A000257",
"A004040",
"A022558"
] | null |
N. J. A. Sloane
| 2023-10-24T07:10:46
|
oeisdata/seq/A004/A004040.seq
|
399db805942d9c789546a792c6749969
|
A004041
|
Scaled sums of odd reciprocals: a(n) = (2*n + 1)!!*(Sum_{k=0..n} 1/(2*k + 1)).
|
[
"1",
"4",
"23",
"176",
"1689",
"19524",
"264207",
"4098240",
"71697105",
"1396704420",
"29985521895",
"703416314160",
"17901641997225",
"491250187505700",
"14459713484342175",
"454441401368236800",
"15188465029114325025",
"537928935889764226500"
] |
[
"nonn"
] | 51
| 0
| 2
|
[
"A000254",
"A002428",
"A004041",
"A024199",
"A028338",
"A049034",
"A109692",
"A161198"
] | null |
Joe Keane (jgk(AT)jgk.org)
| 2024-12-28T00:06:48
|
oeisdata/seq/A004/A004041.seq
|
54750df325846ee6e50838ed17afd080
|
A004042
|
Periods of reciprocals of A006883, starting with first nonzero digit.
|
[
"0",
"142857",
"5882352941176470",
"526315789473684210",
"4347826086956521739130",
"3448275862068965517241379310",
"2127659574468085106382978723404255319148936170",
"1694915254237288135593220338983050847457627118644067796610"
] |
[
"nonn",
"base"
] | 29
| 1
| 2
|
[
"A004042",
"A180340"
] | null |
N. J. A. Sloane
| 2025-02-16T08:32:28
|
oeisdata/seq/A004/A004042.seq
|
b7c2e95fd8e95ee80e35aeb545a32154
|
A004043
|
The coding-theoretic function A(n,8,8).
|
[
"1",
"1",
"1",
"1",
"3",
"3",
"7",
"15",
"30",
"34"
] |
[
"nonn",
"hard",
"more"
] | 20
| 8
| 5
|
[
"A004043",
"A005851",
"A005852",
"A005853",
"A005866",
"A030069"
] | null |
N. J. A. Sloane
| 2025-06-16T15:58:30
|
oeisdata/seq/A004/A004043.seq
|
9b8c8ae0d9fd94e7d52240503e36bf06
|
A004044
|
The classic football pool problem: size of minimal covering code in {0,1,2}^n with covering radius 1.
|
[
"1",
"1",
"3",
"5",
"9",
"27"
] |
[
"nonn",
"hard",
"more",
"nice"
] | 88
| 0
| 3
|
[
"A004044",
"A060439"
] | null |
N. J. A. Sloane
| 2021-08-08T11:28:46
|
oeisdata/seq/A004/A004044.seq
|
efb0a3a449abe661cf1e541d2eadcf52
|
A004045
|
Minimal size of binary code of length n such that every vector is within distance 1 of at least 2 codewords.
|
[
"2",
"3",
"4",
"8",
"12",
"20",
"32"
] |
[
"nonn",
"hard",
"more"
] | 28
| 1
| 1
| null | null |
N. J. A. Sloane
| 2020-03-03T23:38:39
|
oeisdata/seq/A004/A004045.seq
|
81724e103597b8912acc48e79b8b3952
|
A004046
|
Theta series of extremal 3-modular even 24-dimensional lattice with minimal norm 6 and det = 3^12.
|
[
"1",
"0",
"0",
"26208",
"530712",
"6368544",
"47331648",
"256864608",
"1116087336",
"4092877152",
"12996075456",
"37058557536",
"96952754808",
"232778774592",
"526258264896",
"1128148021728",
"2286143305992",
"4451523096384",
"8386247967552",
"15130902687264",
"26614339616592",
"45684687301344"
] |
[
"nonn"
] | 33
| 0
| 4
|
[
"A004046",
"A107657"
] | null |
N. J. A. Sloane
| 2022-09-08T08:44:32
|
oeisdata/seq/A004/A004046.seq
|
14d893cfa58382b6f7f05948cfe43caf
|
A004047
|
The coding-theoretic function A(n,10,9).
|
[
"1",
"1",
"1",
"1",
"1",
"2",
"3",
"4",
"6",
"10",
"19"
] |
[
"nonn",
"hard",
"more"
] | 14
| 9
| 6
| null | null |
N. J. A. Sloane
| 2025-06-16T15:58:40
|
oeisdata/seq/A004/A004047.seq
|
0ad21c91c71e3e4526b5f8576b91266b
|
A004048
|
Theta series of 14-dimensional extremal 3-modular lattice with det 3^7, minimal norm 4, group 2 X G_2(3).
|
[
"1",
"0",
"756",
"8736",
"44226",
"187488",
"531468",
"1314144",
"3097332",
"6141408",
"10968048",
"21258720",
"34038186",
"53778816",
"88943400",
"131804064",
"184024386",
"289650816",
"387420516",
"524343456",
"756139104",
"992308512"
] |
[
"nonn"
] | 14
| 0
| 3
| null | null |
N. J. A. Sloane
| 2024-06-14T22:31:09
|
oeisdata/seq/A004/A004048.seq
|
7f7f44592cdc254bbfe06211064b5d1a
|
A004049
|
Erroneous version of A006967.
|
[
"1",
"1",
"4",
"4",
"8",
"24",
"32",
"40",
"120",
"296"
] |
[
"dead"
] | 10
| 1
| 3
| null | null |
N. J. A. Sloane
| 2023-10-24T06:17:06
|
oeisdata/seq/A004/A004049.seq
|
ecbebae0b0f3a235e40870043048c9df
|
A004050
|
Numbers of the form 2^j + 3^k, for j and k >= 0.
|
[
"2",
"3",
"4",
"5",
"7",
"9",
"10",
"11",
"13",
"17",
"19",
"25",
"28",
"29",
"31",
"33",
"35",
"41",
"43",
"59",
"65",
"67",
"73",
"82",
"83",
"85",
"89",
"91",
"97",
"113",
"129",
"131",
"137",
"145",
"155",
"209",
"244",
"245",
"247",
"251",
"257",
"259",
"265",
"275",
"283",
"307",
"337",
"371",
"499",
"513",
"515",
"521",
"539",
"593",
"730",
"731",
"733",
"737",
"745",
"755"
] |
[
"nonn"
] | 53
| 1
| 1
|
[
"A000079",
"A000243",
"A004050",
"A004051",
"A085634",
"A219835",
"A226806",
"A226832"
] | null |
N. J. A. Sloane
| 2022-10-28T07:15:48
|
oeisdata/seq/A004/A004050.seq
|
d34b6cbd548f3f3df0f03ebe7efbab64
|
A004051
|
Primes of the form 2^a + 3^b.
|
[
"2",
"3",
"5",
"7",
"11",
"13",
"17",
"19",
"29",
"31",
"41",
"43",
"59",
"67",
"73",
"83",
"89",
"97",
"113",
"131",
"137",
"251",
"257",
"283",
"307",
"337",
"499",
"521",
"593",
"733",
"761",
"857",
"1033",
"1051",
"1753",
"2129",
"2203",
"2251",
"2699",
"2777",
"4099",
"4177",
"4339",
"6563",
"6569",
"6577",
"6689",
"8219",
"8273",
"8609",
"10657",
"14753"
] |
[
"nonn"
] | 28
| 1
| 1
|
[
"A004050",
"A004051",
"A010051"
] | null |
N. J. A. Sloane
| 2016-04-25T12:04:59
|
oeisdata/seq/A004/A004051.seq
|
7597797d8f919555ad470bda207c19ff
|
A004052
|
The coding-theoretic function A(n,14,8).
|
[
"1",
"1",
"1",
"1",
"1",
"1",
"1",
"2",
"2",
"2",
"2",
"2",
"2",
"3",
"3",
"3",
"3",
"3",
"4",
"4",
"4",
"4",
"5",
"5",
"5",
"6",
"6",
"7",
"9",
"9",
"9",
"10",
"10",
"11",
"12",
"12",
"13",
"15",
"17",
"18",
"19",
"21",
"25",
"26"
] |
[
"nonn",
"more"
] | 20
| 8
| 8
| null | null |
N. J. A. Sloane
| 2025-06-16T15:51:27
|
oeisdata/seq/A004/A004052.seq
|
a651b809bd6f260d451d0d49b6a3ffef
|
A004053
|
For m=2,3,..., write m in bases 2,3,..,m.
|
[
"10",
"11",
"10",
"100",
"11",
"10",
"101",
"12",
"11",
"10",
"110",
"20",
"12",
"11",
"10",
"111",
"21",
"13",
"12",
"11",
"10",
"1000",
"22",
"20",
"13",
"12",
"11",
"10",
"1001",
"100",
"21",
"14",
"13",
"12",
"11",
"10",
"1010",
"101",
"22",
"20",
"14",
"13",
"12",
"11",
"10",
"1011",
"102",
"23",
"21",
"15",
"14",
"13",
"12",
"11",
"10",
"1100",
"110",
"30",
"22",
"20",
"15",
"14",
"13",
"12",
"11",
"10"
] |
[
"nonn",
"base",
"tabl"
] | 23
| 2
| 1
|
[
"A004053",
"A007088",
"A007090",
"A007091",
"A007092",
"A007093",
"A007094",
"A007095"
] | null |
Johan Boye (johbo(AT)ida.liu.se)
| 2024-12-01T15:40:01
|
oeisdata/seq/A004/A004053.seq
|
83857a11d932bf1d51e3097ca6ab2591
|
A004054
|
Expansion of (1-x)/((1+x)*(1-2*x)*(1-3*x)).
|
[
"1",
"3",
"11",
"35",
"111",
"343",
"1051",
"3195",
"9671",
"29183",
"87891",
"264355",
"794431",
"2386023",
"7163531",
"21501515",
"64526391",
"193622863",
"580955971",
"1743042675",
"5229477551",
"15689131703",
"47068793211",
"141209175835",
"423633119911",
"1270910544543",
"3812754003251",
"11438306748995"
] |
[
"nonn",
"easy"
] | 57
| 0
| 2
|
[
"A000244",
"A001045",
"A001047",
"A004054",
"A078008"
] | null |
N. J. A. Sloane
| 2023-12-02T15:23:13
|
oeisdata/seq/A004/A004054.seq
|
836d4590e3a20c18bdc513e4d72b8aaa
|
A004055
|
((p-1)/2)! mod p for odd primes p.
|
[
"1",
"2",
"6",
"10",
"5",
"13",
"18",
"1",
"12",
"1",
"31",
"9",
"42",
"46",
"23",
"1",
"11",
"66",
"1",
"27",
"78",
"1",
"34",
"22",
"91",
"102",
"1",
"33",
"15",
"126",
"130",
"37",
"1",
"44",
"1",
"129",
"162",
"1",
"80",
"178",
"162",
"190",
"81",
"183",
"198",
"1",
"1",
"226",
"122",
"144",
"1",
"64",
"1",
"16",
"262",
"187",
"1",
"217",
"53",
"1",
"138",
"1",
"1",
"288",
"114",
"1",
"189"
] |
[
"nonn"
] | 36
| 1
| 2
|
[
"A004055",
"A058302",
"A065091"
] | null |
Jeffrey Shallit, Dec 11 1996
| 2025-01-16T13:01:42
|
oeisdata/seq/A004/A004055.seq
|
e3b250b50c3a81c13e4c56a8ed7db5ec
|
A004056
|
The coding-theoretic function A(n,14,12).
|
[
"1",
"1",
"1",
"1",
"1",
"1",
"1",
"2",
"2",
"3",
"4",
"4",
"6",
"8",
"13"
] |
[
"nonn",
"hard",
"more"
] | 15
| 12
| 8
| null | null |
N. J. A. Sloane
| 2025-06-17T10:25:53
|
oeisdata/seq/A004/A004056.seq
|
5aa22a51651e443d756281a0ffb07f7f
|
A004057
|
Expansion of (1-x)/( (1+x)*(1-2*x)*(1-3*x)*(1-4*x)).
|
[
"1",
"7",
"39",
"191",
"875",
"3843",
"16423",
"68887",
"285219",
"1170059",
"4768127",
"19336863",
"78141883",
"314953555",
"1266977751",
"5089412519",
"20422176467",
"81882328731",
"328110270895",
"1314184126255",
"5261965982571",
"21063553061987"
] |
[
"nonn",
"easy"
] | 17
| 0
| 2
|
[
"A004057",
"A099110"
] | null |
N. J. A. Sloane
| 2022-09-08T08:44:32
|
oeisdata/seq/A004/A004057.seq
|
8c4d81a116668c59cff8ba5f2e3b9a06
|
A004058
|
Expansion of (1-x)/( (1+x)*(1-2*x)*(1-3*x)*(1-4*x)*(1-5*x)).
|
[
"1",
"12",
"99",
"686",
"4305",
"25368",
"143263",
"785202",
"4211229",
"22226204",
"115899147",
"598832598",
"3072304873",
"15676477920",
"79649367351",
"403336249274",
"2037103422837",
"10267399442916",
"51665107485475"
] |
[
"nonn",
"easy"
] | 14
| 0
| 2
|
[
"A004058",
"A099111"
] | null |
N. J. A. Sloane
| 2022-09-08T08:44:32
|
oeisdata/seq/A004/A004058.seq
|
98253abb30cecc116e99303844296ecc
|
A004059
|
a(n) gives position of first n in A057561.
|
[
"1",
"2",
"4",
"5",
"6",
"8",
"9",
"11",
"13",
"14",
"15",
"17",
"18",
"20",
"22",
"23",
"24",
"26",
"28",
"29",
"30",
"32",
"34",
"35",
"36",
"38",
"40",
"41",
"42",
"43",
"45",
"47",
"48",
"50",
"51",
"53",
"55",
"56",
"57",
"59",
"60",
"61",
"64"
] |
[
"nonn"
] | 20
| 1
| 2
|
[
"A004059",
"A057561",
"A094708"
] |
[
"M0949"
] |
N. J. A. Sloane
| 2023-10-24T06:19:00
|
oeisdata/seq/A004/A004059.seq
|
7db7551557b7d1067314df4a84af68dc
|
A004060
|
Erroneous version of A028491.
|
[
"3",
"7",
"13",
"71",
"103",
"541",
"1019",
"1367",
"1627",
"4177",
"9011",
"9551"
] |
[
"dead"
] | 4
| 1
| 1
| null | null | null | 1999-12-11T03:00:00
|
oeisdata/seq/A004/A004060.seq
|
e6866d16647ae7346a81bdee0c4a701a
|
A004061
|
Numbers k such that (5^k - 1)/4 is prime.
|
[
"3",
"7",
"11",
"13",
"47",
"127",
"149",
"181",
"619",
"929",
"3407",
"10949",
"13241",
"13873",
"16519",
"201359",
"396413",
"1888279",
"3300593"
] |
[
"hard",
"nonn",
"more"
] | 73
| 1
| 1
|
[
"A004061",
"A080130"
] |
[
"M2620"
] |
N. J. A. Sloane
| 2025-04-25T04:27:24
|
oeisdata/seq/A004/A004061.seq
|
7d9caa753e00642528085eca58a2ed47
|
A004062
|
Numbers k such that (6^k - 1)/5 is prime.
|
[
"2",
"3",
"7",
"29",
"71",
"127",
"271",
"509",
"1049",
"6389",
"6883",
"10613",
"19889",
"79987",
"608099",
"1365019",
"3360347"
] |
[
"hard",
"more",
"nonn"
] | 69
| 1
| 1
| null |
[
"M0861"
] |
N. J. A. Sloane
| 2025-04-25T04:33:19
|
oeisdata/seq/A004/A004062.seq
|
c424416c36bffd7d88f784c9de5ef53d
|
A004063
|
Numbers k such that (7^k - 1)/6 is prime.
|
[
"5",
"13",
"131",
"149",
"1699",
"14221",
"35201",
"126037",
"371669",
"1264699"
] |
[
"nonn",
"hard",
"more"
] | 58
| 1
| 1
| null |
[
"M3836"
] |
N. J. A. Sloane
| 2025-04-25T05:26:38
|
oeisdata/seq/A004/A004063.seq
|
5c84e196160eb9c37d813227121a2bd4
|
A004064
|
Numbers k such that (12^k - 1)/11 is prime.
|
[
"2",
"3",
"5",
"19",
"97",
"109",
"317",
"353",
"701",
"9739",
"14951",
"37573",
"46889",
"769543"
] |
[
"nonn",
"hard",
"more"
] | 56
| 1
| 1
| null |
[
"M0744"
] |
N. J. A. Sloane
| 2025-04-25T05:26:56
|
oeisdata/seq/A004/A004064.seq
|
0411f2d16220a1f0c26ae728e0221cfd
|
A004065
|
Define predecessors of n, P(n), to consist of numbers whose binary representation is obtained from that of n by replacing 10 with 01 or changing a final 1 to a 0; then a(0)=1, a(n) = Sum a(P(n)), n>0.
|
[
"1",
"1",
"1",
"1",
"1",
"2",
"2",
"2",
"1",
"3",
"5",
"7",
"5",
"12",
"12",
"12",
"1",
"4",
"9",
"16",
"14",
"42",
"54",
"66",
"14",
"56",
"110",
"176",
"110",
"286",
"286",
"286",
"1",
"5",
"14",
"30",
"28",
"100",
"154",
"220",
"42",
"198",
"462",
"858",
"572",
"1716",
"2002",
"2288",
"42",
"240",
"702",
"1560",
"1274",
"4550",
"6552",
"8840",
"1274",
"5824",
"12376"
] |
[
"nonn",
"base"
] | 28
| 0
| 6
|
[
"A003121",
"A004065"
] | null |
David W. Wilson, Jan 29 2000
| 2024-08-28T09:37:31
|
oeisdata/seq/A004/A004065.seq
|
300133209131d870f910ea5acef29f25
|
A004066
|
Number of simple regular trivalent bicolored graphs with 2n nodes.
|
[
"0",
"0",
"1",
"1",
"2",
"6",
"14",
"41",
"157",
"725",
"4196",
"29817",
"246646",
"2297088",
"23503564",
"260265650",
"3090341095",
"39101587595",
"524783295041",
"7443251159470",
"111222017297268",
"1746166043555813",
"28734210790531045",
"494526547845483641",
"8883866458982018870",
"166286444108288113541",
"3237719185652343485853",
"65477290060076644381373"
] |
[
"nonn"
] | 19
| 1
| 5
|
[
"A000512",
"A000840",
"A004066",
"A006823",
"A008325"
] | null |
Gunnar Brinkmann, Brendan McKay and Eric Rogoyski
| 2020-04-03T17:25:42
|
oeisdata/seq/A004/A004066.seq
|
c37116cf2ddee6f52d9347ceda8a13dc
|
A004067
|
The coding-theoretic function A(n,6,7).
|
[
"1",
"1",
"1",
"3",
"6",
"12",
"26",
"42",
"69"
] |
[
"nonn",
"hard",
"more"
] | 20
| 7
| 4
| null | null |
N. J. A. Sloane
| 2025-06-16T15:53:01
|
oeisdata/seq/A004/A004067.seq
|
89daab73cd9e1f9cfe068c835f934d74
|
A004068
|
Number of atoms in a decahedron with n shells.
|
[
"0",
"1",
"7",
"23",
"54",
"105",
"181",
"287",
"428",
"609",
"835",
"1111",
"1442",
"1833",
"2289",
"2815",
"3416",
"4097",
"4863",
"5719",
"6670",
"7721",
"8877",
"10143",
"11524",
"13025",
"14651",
"16407",
"18298",
"20329",
"22505",
"24831",
"27312",
"29953",
"32759",
"35735",
"38886",
"42217",
"45733",
"49439"
] |
[
"nonn",
"easy"
] | 78
| 0
| 3
|
[
"A000292",
"A000447",
"A000578",
"A004006",
"A004068",
"A004126",
"A004188",
"A004466",
"A004467",
"A005891",
"A005900",
"A006003",
"A006322",
"A006527",
"A007588",
"A010001",
"A062025",
"A063521",
"A063522",
"A063523",
"A081436",
"A100145",
"A215630"
] | null |
Albert D. Rich (AlbertRich(AT)msn.com)
| 2025-04-02T03:04:32
|
oeisdata/seq/A004/A004068.seq
|
39483443ba589fa4a32bf75dd4f1e35c
|
A004069
|
Numbers of points in nontrivial partial geometries.
|
[
"15",
"27",
"40",
"45",
"64"
] |
[
"nonn",
"hard"
] | 6
| 1
| 1
| null | null |
N. J. A. Sloane
| 2023-10-24T06:19:30
|
oeisdata/seq/A004/A004069.seq
|
1b6ed0df8e380ada1d5dcbfd19fa0ddb
|
A004070
|
Table of Whitney numbers W(n,k) read by antidiagonals, where W(n,k) is maximal number of pieces into which n-space is sliced by k hyperplanes, n >= 0, k >= 0.
|
[
"1",
"1",
"1",
"1",
"2",
"1",
"1",
"2",
"3",
"1",
"1",
"2",
"4",
"4",
"1",
"1",
"2",
"4",
"7",
"5",
"1",
"1",
"2",
"4",
"8",
"11",
"6",
"1",
"1",
"2",
"4",
"8",
"15",
"16",
"7",
"1",
"1",
"2",
"4",
"8",
"16",
"26",
"22",
"8",
"1",
"1",
"2",
"4",
"8",
"16",
"31",
"42",
"29",
"9",
"1",
"1",
"2",
"4",
"8",
"16",
"32",
"57",
"64",
"37",
"10",
"1",
"1",
"2",
"4",
"8",
"16",
"32",
"63",
"99",
"93",
"46",
"11",
"1",
"1",
"2",
"4",
"8",
"16",
"32",
"64",
"120",
"163"
] |
[
"tabl",
"nonn",
"easy",
"nice"
] | 85
| 0
| 5
|
[
"A000012",
"A000027",
"A000071",
"A000079",
"A000124",
"A000125",
"A000127",
"A000225",
"A000295",
"A002662",
"A002663",
"A002664",
"A004070",
"A006261",
"A007799",
"A008859",
"A008860",
"A008861",
"A008862",
"A008863",
"A035038",
"A035039",
"A035040",
"A035041",
"A035042",
"A052509",
"A178522",
"A178524"
] | null |
N. J. A. Sloane
| 2025-01-08T09:27:46
|
oeisdata/seq/A004/A004070.seq
|
82063c90ef761116c5c022c8ac763d39
|
A004071
|
Start with a(0)=1; replace each i with 12...i, then add 1 to final digit.
|
[
"1",
"2",
"13",
"1124",
"11121235",
"1111211212312346",
"11111211121121231121231234123457",
"1111112111121112112123111211212311212312341121231234123451234568"
] |
[
"nonn",
"base"
] | 15
| 0
| 2
| null | null |
N. J. A. Sloane
| 2017-03-31T22:51:27
|
oeisdata/seq/A004/A004071.seq
|
5595df7de744d85ad5cd57168274ae9a
|
A004072
|
Read the terms of A004071 backwards.
|
[
"1",
"2",
"31",
"4211",
"53212111",
"6432132121121111",
"75432143213212113212112111211111",
"8654321543214321321211432132121132121121113212112111211112111111"
] |
[
"nonn"
] | 12
| 0
| 2
| null | null |
N. J. A. Sloane
| 2023-10-24T06:20:43
|
oeisdata/seq/A004/A004072.seq
|
4d9ed232c0b90e546e5e359a1097856d
|
A004073
|
Start with a(1)=1; to get a(n) replace each i in a(n-1) with 12...i, then append n.
|
[
"1",
"12",
"1123",
"11121234",
"1111211212312345",
"11111211121121231121231234123456",
"1111112111121112112123111211212311212312341121231234123451234567"
] |
[
"nonn",
"base"
] | 15
| 1
| 2
| null | null |
N. J. A. Sloane
| 2017-03-31T22:50:57
|
oeisdata/seq/A004/A004073.seq
|
47b46ed7f4fdada0364e4b9c1dd23239
|
A004074
|
a(n) = 2*A004001(n) - n, where A004001 is the Hofstadter-Conway $10000 sequence.
|
[
"1",
"0",
"1",
"0",
"1",
"2",
"1",
"0",
"1",
"2",
"3",
"2",
"3",
"2",
"1",
"0",
"1",
"2",
"3",
"4",
"3",
"4",
"5",
"4",
"5",
"4",
"3",
"4",
"3",
"2",
"1",
"0",
"1",
"2",
"3",
"4",
"5",
"4",
"5",
"6",
"7",
"6",
"7",
"8",
"7",
"8",
"7",
"6",
"7",
"8",
"7",
"8",
"7",
"6",
"7",
"6",
"5",
"4",
"5",
"4",
"3",
"2",
"1",
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"5",
"6",
"7",
"8",
"9",
"8",
"9",
"10",
"11",
"10",
"11",
"12",
"11",
"12",
"11",
"10",
"11",
"12",
"13",
"12",
"13",
"14",
"13",
"14",
"13",
"12"
] |
[
"nonn"
] | 35
| 1
| 6
|
[
"A004001",
"A004074",
"A082590",
"A213057",
"A233270",
"A249071"
] | null |
N. J. A. Sloane
| 2019-11-23T04:08:51
|
oeisdata/seq/A004/A004074.seq
|
1cc41593f4fb8a0756dcdff3cbf934c6
|
A004075
|
Number of Skolem sequences of order n.
|
[
"1",
"0",
"0",
"6",
"10",
"0",
"0",
"504",
"2656",
"0",
"0",
"455936",
"3040560",
"0",
"0",
"1400156768",
"12248982496",
"0",
"0",
"11435578798976",
"123564928167168",
"0",
"0",
"204776117691241344",
"2634563519776965376",
"0",
"0",
"7064747252076429464064",
"105435171495207196553472",
"0",
"0"
] |
[
"nonn",
"more"
] | 45
| 1
| 4
|
[
"A004075",
"A014552",
"A059106",
"A176127",
"A268537"
] | null |
N. J. A. Sloane
| 2023-10-24T06:22:21
|
oeisdata/seq/A004/A004075.seq
|
fc6ff109044aef988bf8343437f41c3c
|
A004076
|
Number of hooked Skolem sequences of order n.
|
[
"0",
"1",
"2",
"0",
"0",
"38",
"124",
"0",
"0",
"12808",
"72648",
"0",
"0",
"21878816",
"168870048",
"0",
"0",
"113071735648",
"1105816948032",
"0",
"0",
"1395701792232832"
] |
[
"nonn",
"more"
] | 27
| 1
| 3
| null | null |
N. J. A. Sloane
| 2023-10-24T19:24:00
|
oeisdata/seq/A004/A004076.seq
|
fb50caaed5e679e3c597da5c773ef7e5
|
A004077
|
Number of extended Skolem sequences of order n.
|
[
"2",
"2",
"6",
"22",
"48",
"160",
"636",
"3556",
"19488",
"95872",
"594320",
"4459888",
"32131648",
"227072544",
"1875064880",
"17851780784",
"165367171136",
"1506506453568",
"15540217445728",
"179708231523680",
"2034547787823488",
"22716589497430656"
] |
[
"nonn",
"more"
] | 30
| 1
| 1
| null | null |
N. J. A. Sloane
| 2023-10-24T07:02:09
|
oeisdata/seq/A004/A004077.seq
|
c467836ee445ea443c3ff0f40e17a237
|
A004078
|
Number of Tuscan squares of order n.
|
[
"1",
"0",
"1",
"0",
"736",
"466144"
] |
[
"nonn",
"hard"
] | 10
| 2
| 5
| null | null |
N. J. A. Sloane
| 2023-10-24T10:09:43
|
oeisdata/seq/A004/A004078.seq
|
a893181bbc133da1ac4812326f932117
|
A004079
|
a(n) = maximal m such that an m X n Florentine rectangle exists.
|
[
"1",
"2",
"2",
"4",
"4",
"6",
"6",
"7",
"8",
"10",
"10",
"12"
] |
[
"nonn",
"hard"
] | 7
| 1
| 2
| null | null |
N. J. A. Sloane
| 2023-10-24T06:27:25
|
oeisdata/seq/A004/A004079.seq
|
cf4c8233936c6edcb7c690ff1f228d08
|
A004080
|
Least k such that H(k) >= n, where H(k) is the harmonic number Sum_{i=1..k} 1/i.
|
[
"0",
"1",
"4",
"11",
"31",
"83",
"227",
"616",
"1674",
"4550",
"12367",
"33617",
"91380",
"248397",
"675214",
"1835421",
"4989191",
"13562027",
"36865412",
"100210581",
"272400600",
"740461601",
"2012783315",
"5471312310",
"14872568831",
"40427833596",
"109894245429",
"298723530401",
"812014744422"
] |
[
"nonn",
"nice"
] | 82
| 0
| 3
|
[
"A002387",
"A004080"
] | null |
N. J. A. Sloane, Clark Kimberling
| 2025-02-16T08:32:28
|
oeisdata/seq/A004/A004080.seq
|
0e9b14189f9d298e985ae46273df6250
|
A004081
|
a(n) = n-th positive integer such that only one integer lies between exp(s(m)) and exp(s(m+1)), where s(m) = 1 + 1/2 + 1/3 + . . . + 1/m.
|
[
"4",
"8",
"13",
"17",
"22",
"26",
"31",
"36",
"40",
"45",
"49",
"54",
"58",
"63",
"68",
"72",
"77",
"81",
"86",
"90",
"95",
"99",
"104",
"109",
"113",
"118",
"122",
"127",
"131",
"136",
"141",
"145",
"150",
"154",
"159",
"163",
"168",
"173",
"177",
"182",
"186",
"191",
"195",
"200"
] |
[
"nonn"
] | 13
| 1
| 1
| null | null |
Clark Kimberling
| 2013-05-30T16:57:29
|
oeisdata/seq/A004/A004081.seq
|
3ab2e266da1955c020ec4c1491924721
|
A004082
|
Numbers k such that sin(k-1) <= 0 and sin(k) > 0.
|
[
"1",
"7",
"13",
"19",
"26",
"32",
"38",
"44",
"51",
"57",
"63",
"70",
"76",
"82",
"88",
"95",
"101",
"107",
"114",
"120",
"126",
"132",
"139",
"145",
"151",
"158",
"164",
"170",
"176",
"183",
"189",
"195",
"202",
"208",
"214",
"220",
"227",
"233",
"239",
"246",
"252",
"258",
"264",
"271",
"277",
"283",
"290",
"296"
] |
[
"nonn"
] | 46
| 1
| 2
|
[
"A004082",
"A004084",
"A038130",
"A066643",
"A277690"
] | null |
Clark Kimberling
| 2025-03-21T09:39:18
|
oeisdata/seq/A004/A004082.seq
|
d7be581f67acb9e09408493b6235cbe0
|
A004083
|
Numbers k such that cos(k-1) <= 0 and cos(k) > 0.
|
[
"5",
"11",
"18",
"24",
"30",
"37",
"43",
"49",
"55",
"62",
"68",
"74",
"81",
"87",
"93",
"99",
"106",
"112",
"118",
"125",
"131",
"137",
"143",
"150",
"156",
"162",
"169",
"175",
"181",
"187",
"194",
"200",
"206",
"213",
"219",
"225",
"231",
"238",
"244",
"250",
"257",
"263",
"269",
"275",
"282",
"288",
"294",
"301",
"307",
"313",
"319",
"326",
"332",
"338",
"345"
] |
[
"nonn"
] | 21
| 1
| 1
|
[
"A004083",
"A145005"
] | null |
Clark Kimberling
| 2021-04-23T01:23:21
|
oeisdata/seq/A004/A004083.seq
|
722e9c339bdc7ed062b5c695117ef3f7
|
A004084
|
a(n) = n-th positive integer k such that tan(k-1) <= 0 and tan(k) > 0.
|
[
"1",
"4",
"7",
"10",
"13",
"16",
"19",
"22",
"26",
"29",
"32",
"35",
"38",
"41",
"44",
"48",
"51",
"54",
"57",
"60",
"63",
"66",
"70",
"73",
"76",
"79",
"82",
"85",
"88",
"92",
"95",
"98",
"101",
"104",
"107",
"110",
"114",
"117",
"120",
"123",
"126",
"129",
"132",
"136",
"139",
"142",
"145",
"148",
"151",
"154",
"158",
"161",
"164",
"167"
] |
[
"nonn"
] | 16
| 1
| 2
| null | null |
Clark Kimberling
| 2013-03-21T06:36:42
|
oeisdata/seq/A004/A004084.seq
|
5233c68fc8d2d10db39f5ea6a1615c55
|
A004085
|
Sum of digits of Euler totient function of n.
|
[
"1",
"1",
"2",
"2",
"4",
"2",
"6",
"4",
"6",
"4",
"1",
"4",
"3",
"6",
"8",
"8",
"7",
"6",
"9",
"8",
"3",
"1",
"4",
"8",
"2",
"3",
"9",
"3",
"10",
"8",
"3",
"7",
"2",
"7",
"6",
"3",
"9",
"9",
"6",
"7",
"4",
"3",
"6",
"2",
"6",
"4",
"10",
"7",
"6",
"2",
"5",
"6",
"7",
"9",
"4",
"6",
"9",
"10",
"13",
"7",
"6",
"3",
"9",
"5",
"12",
"2",
"12",
"5",
"8",
"6",
"7",
"6",
"9",
"9",
"4",
"9",
"6",
"6",
"15",
"5",
"9",
"4",
"10",
"6",
"10"
] |
[
"nonn",
"base"
] | 24
| 1
| 3
|
[
"A000010",
"A004085",
"A007953",
"A077651"
] | null |
N. J. A. Sloane
| 2022-09-08T08:44:32
|
oeisdata/seq/A004/A004085.seq
|
dca3ebefb2cae9628b86c6ec90736d27
|
A004086
|
Read n backwards (referred to as R(n) in many sequences).
|
[
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"1",
"11",
"21",
"31",
"41",
"51",
"61",
"71",
"81",
"91",
"2",
"12",
"22",
"32",
"42",
"52",
"62",
"72",
"82",
"92",
"3",
"13",
"23",
"33",
"43",
"53",
"63",
"73",
"83",
"93",
"4",
"14",
"24",
"34",
"44",
"54",
"64",
"74",
"84",
"94",
"5",
"15",
"25",
"35",
"45",
"55",
"65",
"75",
"85",
"95",
"6",
"16",
"26",
"36",
"46",
"56",
"66",
"76",
"86",
"96",
"7",
"17",
"27",
"37",
"47"
] |
[
"nonn",
"base",
"nice",
"look"
] | 142
| 0
| 3
|
[
"A004086",
"A004185",
"A004186",
"A009996",
"A030101",
"A030102",
"A030103",
"A030104",
"A030105",
"A030107",
"A030108",
"A073138",
"A188649",
"A221714"
] | null |
N. J. A. Sloane
| 2025-05-15T01:04:33
|
oeisdata/seq/A004/A004086.seq
|
af8b07961c5f7dda7f2a52d24c4d5212
|
A004087
|
Primes written backwards.
|
[
"2",
"3",
"5",
"7",
"11",
"31",
"71",
"91",
"32",
"92",
"13",
"73",
"14",
"34",
"74",
"35",
"95",
"16",
"76",
"17",
"37",
"97",
"38",
"98",
"79",
"101",
"301",
"701",
"901",
"311",
"721",
"131",
"731",
"931",
"941",
"151",
"751",
"361",
"761",
"371",
"971",
"181",
"191",
"391",
"791",
"991",
"112",
"322",
"722",
"922",
"332",
"932",
"142",
"152",
"752",
"362",
"962",
"172"
] |
[
"nonn",
"base",
"look"
] | 37
| 1
| 1
|
[
"A000040",
"A004087"
] | null |
N. J. A. Sloane
| 2022-06-24T20:14:26
|
oeisdata/seq/A004/A004087.seq
|
7ff1dbce2165d8e96e72637fbdf918bd
|
A004088
|
Sum of digits of number of partitions of n.
|
[
"1",
"1",
"2",
"3",
"5",
"7",
"2",
"6",
"4",
"3",
"6",
"11",
"14",
"2",
"9",
"14",
"6",
"18",
"16",
"13",
"15",
"18",
"3",
"13",
"18",
"23",
"15",
"4",
"19",
"20",
"15",
"20",
"24",
"9",
"7",
"24",
"31",
"19",
"14",
"18",
"24",
"24",
"20",
"18",
"25",
"25",
"24",
"23",
"24",
"23",
"16",
"30",
"33",
"27",
"28",
"25",
"26",
"21",
"17",
"22",
"38",
"15",
"16",
"33",
"22",
"23",
"17",
"47",
"33",
"29",
"42",
"33",
"37",
"43",
"29",
"30",
"38"
] |
[
"nonn",
"base"
] | 8
| 0
| 3
|
[
"A000041",
"A004088"
] | null |
N. J. A. Sloane
| 2023-10-24T19:25:22
|
oeisdata/seq/A004/A004088.seq
|
bd996c66b014a37b4fac64e84824b0ee
|
A004089
|
Reverse digits of number of partitions of n.
|
[
"1",
"1",
"2",
"3",
"5",
"7",
"11",
"51",
"22",
"3",
"24",
"65",
"77",
"101",
"531",
"671",
"132",
"792",
"583",
"94",
"726",
"297",
"2001",
"5521",
"5751",
"8591",
"6342",
"103",
"8173",
"5654",
"4065",
"2486",
"9438",
"34101",
"1321",
"38841",
"77971",
"73612",
"51062",
"58113",
"83373",
"38544",
"47135",
"16236",
"57157",
"43198",
"855501",
"457421",
"372741",
"525371"
] |
[
"nonn",
"base"
] | 12
| 0
| 3
|
[
"A000041",
"A004086",
"A004089"
] | null |
N. J. A. Sloane
| 2025-04-25T23:39:31
|
oeisdata/seq/A004/A004089.seq
|
54565f4f8a47468d0dd4aac71eef738f
|
A004090
|
Sum of digits of Fibonacci numbers.
|
[
"0",
"1",
"1",
"2",
"3",
"5",
"8",
"4",
"3",
"7",
"10",
"17",
"9",
"8",
"17",
"7",
"24",
"22",
"19",
"14",
"24",
"20",
"17",
"28",
"27",
"19",
"19",
"29",
"21",
"23",
"17",
"31",
"30",
"34",
"37",
"35",
"27",
"35",
"44",
"43",
"24",
"31",
"46",
"41",
"33",
"29",
"35",
"37",
"54",
"55",
"46",
"29",
"48",
"41",
"53",
"58",
"48",
"52",
"73",
"44",
"54",
"53",
"62",
"61",
"51",
"67",
"73",
"59"
] |
[
"nonn",
"base",
"easy",
"changed"
] | 44
| 0
| 4
|
[
"A000045",
"A004090",
"A007953",
"A010888",
"A030132",
"A068500",
"A246558",
"A261587",
"A45"
] | null |
N. J. A. Sloane
| 2025-07-10T14:00:58
|
oeisdata/seq/A004/A004090.seq
|
7dd07e0ee306f85c0646209f1ef69f4f
|
A004091
|
Fibonacci numbers written backwards.
|
[
"0",
"1",
"1",
"2",
"3",
"5",
"8",
"31",
"12",
"43",
"55",
"98",
"441",
"332",
"773",
"16",
"789",
"7951",
"4852",
"1814",
"5676",
"64901",
"11771",
"75682",
"86364",
"52057",
"393121",
"814691",
"118713",
"922415",
"40238",
"9626431",
"9038712",
"8754253",
"7882075",
"5647229",
"25303941",
"71875142",
"96188093",
"68954236",
"551433201",
"141085561",
"692419762",
"734494334",
"337804107",
"713094311",
"3091136381",
"3705121792"
] |
[
"nonn",
"base"
] | 40
| 0
| 4
|
[
"A000045",
"A004091",
"A004170",
"A014258"
] | null |
N. J. A. Sloane
| 2024-06-21T12:34:30
|
oeisdata/seq/A004/A004091.seq
|
d320726cea4e7010ded6e7618cba22f9
|
A004092
|
Sum of digits of even numbers.
|
[
"0",
"2",
"4",
"6",
"8",
"1",
"3",
"5",
"7",
"9",
"2",
"4",
"6",
"8",
"10",
"3",
"5",
"7",
"9",
"11",
"4",
"6",
"8",
"10",
"12",
"5",
"7",
"9",
"11",
"13",
"6",
"8",
"10",
"12",
"14",
"7",
"9",
"11",
"13",
"15",
"8",
"10",
"12",
"14",
"16",
"9",
"11",
"13",
"15",
"17",
"1",
"3",
"5"
] |
[
"nonn",
"base",
"easy"
] | 22
| 0
| 2
|
[
"A004092",
"A007953",
"A169964"
] | null |
N. J. A. Sloane, Dec 11 1996
| 2023-04-29T08:10:16
|
oeisdata/seq/A004/A004092.seq
|
643a43d04adfeda7e49dd3bf56c14b8a
|
A004093
|
Even numbers written backwards.
|
[
"0",
"2",
"4",
"6",
"8",
"1",
"21",
"41",
"61",
"81",
"2",
"22",
"42",
"62",
"82",
"3",
"23",
"43",
"63",
"83",
"4",
"24",
"44",
"64",
"84",
"5",
"25",
"45",
"65",
"85",
"6",
"26",
"46",
"66",
"86",
"7",
"27",
"47",
"67",
"87",
"8",
"28",
"48",
"68",
"88",
"9",
"29",
"49",
"69",
"89",
"1",
"201",
"401",
"601",
"801",
"11",
"211",
"411",
"611",
"811",
"21",
"221",
"421",
"621",
"821",
"31"
] |
[
"nonn",
"base",
"look"
] | 25
| 0
| 2
|
[
"A004086",
"A004093"
] | null |
N. J. A. Sloane
| 2022-11-14T16:06:57
|
oeisdata/seq/A004/A004093.seq
|
bc8f4a4828777af86df807aec8d31bad
|
A004094
|
Powers of 2 written backwards.
|
[
"1",
"2",
"4",
"8",
"61",
"23",
"46",
"821",
"652",
"215",
"4201",
"8402",
"6904",
"2918",
"48361",
"86723",
"63556",
"270131",
"441262",
"882425",
"6758401",
"2517902",
"4034914",
"8068838",
"61277761",
"23445533",
"46880176",
"827712431",
"654534862",
"219078635",
"4281473701",
"8463847412",
"6927694924",
"2954399858",
"48196897171"
] |
[
"nonn",
"base",
"easy"
] | 50
| 0
| 2
|
[
"A000079",
"A000244",
"A004086",
"A004094",
"A004167",
"A014963",
"A028909",
"A028910",
"A036447",
"A057615",
"A057708",
"A102382",
"A102383",
"A102384",
"A102385",
"A163632",
"A263451",
"A321539",
"A321540",
"A321541",
"A321542"
] | null |
N. J. A. Sloane
| 2025-01-07T02:01:00
|
oeisdata/seq/A004/A004094.seq
|
2aadc584f9d6074ff16aa637b0254c5c
|
A004095
|
Sum of digits of Catalan numbers.
|
[
"1",
"1",
"2",
"5",
"5",
"6",
"6",
"15",
"8",
"20",
"29",
"34",
"13",
"22",
"27",
"45",
"36",
"42",
"42",
"42",
"30",
"39",
"48",
"45",
"54",
"54",
"53",
"56",
"65",
"49",
"64",
"73",
"84",
"39",
"75",
"73",
"106",
"79",
"83",
"95",
"77",
"90",
"99",
"90",
"108",
"99",
"90",
"135",
"126",
"117",
"135",
"126",
"135",
"132",
"141"
] |
[
"nonn",
"base"
] | 6
| 0
| 3
|
[
"A000108",
"A004095"
] | null |
N. J. A. Sloane
| 2023-10-24T19:31:13
|
oeisdata/seq/A004/A004095.seq
|
d4bf4abc8f1c8e0ddc22a56bbcc1f04f
|
A004096
|
Catalan numbers written backwards.
|
[
"1",
"1",
"2",
"5",
"41",
"24",
"231",
"924",
"341",
"2684",
"69761",
"68785",
"210802",
"9247",
"444762",
"5484969",
"7675353",
"97446921",
"7836774",
"913627671",
"240214656",
"2076266442",
"4636528419",
"56316950343",
"4237414099821",
"2541046491684",
"25127035376381",
"40061905533596",
"63057159747362"
] |
[
"nonn",
"base"
] | 22
| 0
| 3
|
[
"A000108",
"A004096"
] | null |
N. J. A. Sloane
| 2022-09-08T08:44:32
|
oeisdata/seq/A004/A004096.seq
|
19555c3676dcf48313acc95dcaa8f191
|
A004097
|
Sum of digits of Bell numbers.
|
[
"1",
"1",
"2",
"5",
"6",
"7",
"5",
"22",
"9",
"15",
"28",
"33",
"31",
"37",
"43",
"50",
"32",
"63",
"58",
"50",
"55",
"78",
"69",
"64",
"105",
"94",
"91",
"118",
"104",
"101",
"96",
"121",
"122",
"139",
"141",
"102",
"163",
"150",
"154",
"172",
"145",
"164",
"185",
"186",
"187",
"194",
"184",
"153",
"186",
"172",
"231",
"211",
"226",
"196",
"230",
"266",
"243",
"247",
"248",
"280",
"312",
"285"
] |
[
"nonn",
"base"
] | 12
| 0
| 3
|
[
"A000110",
"A004097",
"A007953"
] | null |
N. J. A. Sloane
| 2022-09-08T08:44:32
|
oeisdata/seq/A004/A004097.seq
|
44b7a9a776c6d61fbe2f47e80d45b964
|
A004098
|
Bell numbers written backwards.
|
[
"1",
"1",
"2",
"5",
"51",
"25",
"302",
"778",
"414",
"74112",
"579511",
"75876",
"7953124",
"73444672",
"223998091",
"5458592831",
"74124108401",
"40896846828",
"951608670286",
"7505022472385",
"27353285142715",
"157651618968474",
"3237448375176054",
"64348055850025144",
"982508492968859544"
] |
[
"nonn",
"base"
] | 24
| 0
| 3
|
[
"A000110",
"A004086",
"A004098"
] | null |
N. J. A. Sloane
| 2022-09-08T08:44:32
|
oeisdata/seq/A004/A004098.seq
|
1515167ce9dfcbbb260d56ff4c5e1ecc
|
A004099
|
Sum of digits of Euler numbers.
|
[
"1",
"1",
"1",
"2",
"5",
"7",
"7",
"11",
"17",
"25",
"13",
"29",
"29",
"34",
"46",
"38",
"41",
"61",
"61",
"65",
"62",
"70",
"85",
"74",
"83",
"88",
"91",
"110",
"113",
"124",
"106",
"128",
"170",
"142",
"157",
"164",
"128",
"178",
"172",
"146",
"176",
"178",
"178",
"209",
"206",
"214",
"247",
"218",
"263",
"268",
"235",
"335",
"284",
"259",
"295",
"254",
"278",
"295",
"283",
"254",
"308",
"313"
] |
[
"nonn",
"base"
] | 10
| 0
| 4
|
[
"A000111",
"A004099",
"A007953"
] | null |
N. J. A. Sloane
| 2023-10-24T19:32:10
|
oeisdata/seq/A004/A004099.seq
|
9ceced35638fdfa5e5ee8965d1a60856
|
A004100
|
Number of labeled nonseparable bipartite graphs on n nodes.
|
[
"0",
"1",
"0",
"3",
"10",
"355",
"6986",
"297619",
"15077658",
"1120452771",
"111765799882",
"15350524923547",
"2875055248515242",
"738416821509929731",
"260316039943139322858",
"126430202628042630866787",
"84814075550928212558332858",
"78847417416749666369637926851"
] |
[
"nonn",
"nice",
"easy"
] | 36
| 1
| 4
|
[
"A001832",
"A004100",
"A013922"
] |
[
"M2878"
] |
N. J. A. Sloane
| 2019-09-04T08:06:22
|
oeisdata/seq/A004/A004100.seq
|
a648e9e0cb14ad5f3249279ed07276ba
|
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