sequence_id stringlengths 7 7 | sequence_name stringlengths 4 573 | sequence listlengths 1 348 | keywords listlengths 1 7 | score int64 1 2.47k | 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 2026-01-19 02:46:49 | filename stringlengths 29 29 | hash stringlengths 32 32 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
A001201 | Number of Steiner triple systems (STS's) on 6n+1 or 6n+3 elements. | [
"1",
"1",
"30",
"840",
"1197504000",
"60281712691200",
"1348410350618155344199680000"
] | [
"nonn",
"nice",
"hard",
"more"
] | 28 | 0 | 3 | [
"A001201",
"A030128",
"A030129",
"A047241",
"A051390"
] | [
"M5214",
"N2268"
] | N. J. A. Sloane | 2022-06-17T03:23:17 | oeisdata/seq/A001/A001201.seq | 151c1cf323f8fba1d64e36b9691a0b08 |
A001202 | a(1)=0, a(2n) = a(n)+1, a(2n+1) = 10*a(n+1). | [
"0",
"1",
"10",
"2",
"100",
"11",
"20",
"3",
"1000",
"101",
"110",
"12",
"200",
"21",
"30",
"4",
"10000",
"1001",
"1010",
"102",
"1100",
"111",
"120",
"13",
"2000",
"201",
"210",
"22",
"300",
"31",
"40",
"5",
"100000",
"10001",
"10010",
"1002",
... | [
"nonn",
"easy"
] | 19 | 1 | 3 | null | null | N. J. A. Sloane | 2022-09-08T08:44:28 | oeisdata/seq/A001/A001202.seq | dfc805d030f40b313d1f1d717df4e0d9 |
A001203 | Simple continued fraction expansion of Pi. | [
"3",
"7",
"15",
"1",
"292",
"1",
"1",
"1",
"2",
"1",
"3",
"1",
"14",
"2",
"1",
"1",
"2",
"2",
"2",
"2",
"1",
"84",
"2",
"1",
"1",
"15",
"3",
"13",
"1",
"4",
"2",
"6",
"6",
"99",
"1",
"2",
"2",
"6",
"3",
"5",
"1",
"1",
"6",
"8",
... | [
"nonn",
"nice",
"cofr"
] | 176 | 0 | 1 | [
"A000796",
"A001203",
"A007541",
"A033089",
"A033090",
"A097545",
"A097546"
] | [
"M2646",
"N1054"
] | N. J. A. Sloane | 2025-12-01T09:36:28 | oeisdata/seq/A001/A001203.seq | 266ccf809f528f3e766c41aa56fa7f63 |
A001204 | Continued fraction for e^2. | [
"7",
"2",
"1",
"1",
"3",
"18",
"5",
"1",
"1",
"6",
"30",
"8",
"1",
"1",
"9",
"42",
"11",
"1",
"1",
"12",
"54",
"14",
"1",
"1",
"15",
"66",
"17",
"1",
"1",
"18",
"78",
"20",
"1",
"1",
"21",
"90",
"23",
"1",
"1",
"24",
"102",
"26",
"1... | [
"nonn",
"easy",
"cofr",
"nice"
] | 49 | 0 | 1 | [
"A001204",
"A003417",
"A004273",
"A005131",
"A058282",
"A072334"
] | [
"M4322",
"N1811"
] | N. J. A. Sloane | 2025-05-04T01:58:26 | oeisdata/seq/A001/A001204.seq | 0f93c82e7b73307aeeb7e71935c82a4d |
A001205 | Number of clouds with n points; number of undirected 2-regular labeled graphs; or number of n X n symmetric matrices with (0,1) entries, trace 0 and all row sums 2. | [
"1",
"0",
"0",
"1",
"3",
"12",
"70",
"465",
"3507",
"30016",
"286884",
"3026655",
"34944085",
"438263364",
"5933502822",
"86248951243",
"1339751921865",
"22148051088480",
"388246725873208",
"7193423109763089",
"140462355821628771",
"2883013994348484940"
] | [
"nonn",
"easy",
"nice"
] | 89 | 0 | 5 | [
"A000985",
"A000986",
"A001205",
"A002137",
"A059441",
"A144163"
] | [
"M2937",
"N1181"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001205.seq | ed5a5e2d8879e79cf4ce1a525132c247 |
A001206 | Number of self-dual monotone Boolean functions of n variables. | [
"0",
"1",
"2",
"4",
"12",
"81",
"2646",
"1422564",
"229809982112",
"423295099074735261880"
] | [
"nonn",
"hard",
"nice",
"more"
] | 118 | 0 | 3 | [
"A000372",
"A001206",
"A006126",
"A007363",
"A014466",
"A051185",
"A059090",
"A305844",
"A326361",
"A326362",
"A326363",
"A326366",
"A326372"
] | [
"M1267",
"N0486"
] | N. J. A. Sloane | 2025-12-30T10:15:13 | oeisdata/seq/A001/A001206.seq | f0e9131254c30016f8daa288313ad1c8 |
A001207 | Number of fixed hexagonal polyominoes with n cells. | [
"1",
"3",
"11",
"44",
"186",
"814",
"3652",
"16689",
"77359",
"362671",
"1716033",
"8182213",
"39267086",
"189492795",
"918837374",
"4474080844",
"21866153748",
"107217298977",
"527266673134",
"2599804551168",
"12849503756579",
"63646233127758",
"315876691291677",
"1570... | [
"nonn",
"nice"
] | 53 | 1 | 2 | [
"A000228",
"A001207",
"A006535",
"A059716",
"A121220"
] | [
"M2897",
"N1162"
] | N. J. A. Sloane | 2024-08-31T09:51:34 | oeisdata/seq/A001/A001207.seq | 1992bcde54ea1498dd6699ef23a53b86 |
A001208 | a(n) = solution to the postage stamp problem with 3 denominations and n stamps. | [
"3",
"8",
"15",
"26",
"35",
"52",
"69",
"89",
"112",
"146",
"172",
"212",
"259",
"302",
"354",
"418",
"476",
"548",
"633",
"714",
"805",
"902",
"1012",
"1127",
"1254",
"1382",
"1524",
"1678",
"1841",
"2010",
"2188",
"2382",
"2584",
"2801",
"3020",
... | [
"nonn",
"nice"
] | 55 | 1 | 1 | [
"A001208",
"A001209",
"A001210",
"A001211",
"A001212",
"A001213",
"A001214",
"A001215",
"A001216",
"A005342",
"A005343",
"A005344",
"A014616",
"A053346",
"A053348",
"A075060",
"A084192",
"A084193",
"A195618",
"A196416"
] | [
"M2721",
"N1351"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001208.seq | 21151cd723d2dc771d81fa9ef826a4f2 |
A001209 | a(n) is the solution to the postage stamp problem with 4 denominations and n stamps. | [
"4",
"12",
"24",
"44",
"71",
"114",
"165",
"234",
"326",
"427",
"547",
"708",
"873",
"1094",
"1383",
"1650",
"1935",
"2304",
"2782",
"3324",
"3812",
"4368",
"5130",
"5892",
"6745",
"7880",
"8913",
"9919",
"11081",
"12376",
"13932",
"15657",
"17242",
... | [
"nonn"
] | 49 | 1 | 1 | [
"A001208",
"A001209",
"A001210",
"A001211",
"A001212",
"A001213",
"A001214",
"A001215",
"A001216",
"A005342",
"A005343",
"A005344",
"A014616",
"A053346",
"A053348",
"A075060",
"A084192",
"A084193",
"A196069",
"A196416"
] | [
"M3432",
"N1568"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001209.seq | f08781c273b43f6ceb1225e5b24d81cd |
A001210 | a(n) is the solution to the postage stamp problem with 5 denominations and n stamps. | [
"5",
"16",
"36",
"70",
"126",
"216",
"345",
"512",
"797",
"1055",
"1475",
"2047",
"2659",
"3403",
"4422",
"5629",
"6865",
"8669",
"10835",
"12903",
"15785",
"18801",
"22456",
"26469",
"31108",
"36949",
"42744",
"49436",
"57033",
"66771",
"75558",
"86303"... | [
"nonn"
] | 43 | 1 | 1 | [
"A001208",
"A001209",
"A001210",
"A001211",
"A001212",
"A001213",
"A001214",
"A001215",
"A001216",
"A005342",
"A005343",
"A005344",
"A014616",
"A053346",
"A053348",
"A075060",
"A084192",
"A084193",
"A196416"
] | [
"M3864",
"N1707"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001210.seq | dd4e65651c5344e5a2386c64cf545d9a |
A001211 | a(n) is the solution to the postage stamp problem with 6 denominations and n stamps. | [
"6",
"20",
"52",
"108",
"211",
"388",
"664",
"1045",
"1617",
"2510",
"3607",
"5118",
"7066",
"9748",
"12793",
"17061",
"22342",
"28874",
"36560",
"45745",
"57814",
"72997",
"87555",
"106888",
"129783"
] | [
"nonn",
"more"
] | 41 | 1 | 1 | [
"A001208",
"A001209",
"A001210",
"A001211",
"A001212",
"A001213",
"A001214",
"A001215",
"A001216",
"A005342",
"A005343",
"A005344",
"A014616",
"A053346",
"A053348",
"A075060",
"A084192",
"A084193",
"A196416"
] | [
"M4136",
"N1836"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001211.seq | 5329da37427ae1cb13263ad8e399a1c9 |
A001212 | a(n) = solution to the postage stamp problem with n denominations and 2 stamps. | [
"2",
"4",
"8",
"12",
"16",
"20",
"26",
"32",
"40",
"46",
"54",
"64",
"72",
"80",
"92",
"104",
"116",
"128",
"140",
"152",
"164",
"180",
"196",
"212"
] | [
"nonn",
"nice",
"more"
] | 109 | 1 | 1 | [
"A001208",
"A001209",
"A001210",
"A001211",
"A001212",
"A001213",
"A001214",
"A001215",
"A001216",
"A005342",
"A005343",
"A005344",
"A006638",
"A014616",
"A053346",
"A053348",
"A075060",
"A084192",
"A084193",
"A123509",
"A196094",
"A196416",
"A234941"
] | [
"M1089",
"N0972"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001212.seq | 6665761d1355ec2d11f3c62aba1a8849 |
A001213 | a(n) is the solution to the postage stamp problem with n denominations and 3 stamps. | [
"3",
"7",
"15",
"24",
"36",
"52",
"70",
"93",
"121",
"154",
"186",
"225",
"271",
"323",
"385",
"450",
"515",
"606",
"684",
"788",
"865",
"977",
"1091",
"1201",
"1361"
] | [
"nonn",
"more"
] | 37 | 1 | 1 | [
"A001208",
"A001209",
"A001210",
"A001211",
"A001212",
"A001213",
"A001214",
"A001215",
"A001216",
"A005342",
"A005343",
"A005344",
"A014616",
"A053346",
"A053348",
"A075060",
"A084192",
"A084193",
"A196416"
] | [
"M2647",
"N1340"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001213.seq | 6bb8b8d5f9cc55cb35ce890c010c4f0e |
A001214 | a(n) is the solution to the postage stamp problem with n denominations and 4 stamps. | [
"4",
"10",
"26",
"44",
"70",
"108",
"162",
"228",
"310",
"422",
"550",
"700",
"878",
"1079",
"1344",
"1606",
"1944",
"2337",
"2766",
"3195",
"3668",
"4251",
"4923",
"5631",
"6429"
] | [
"nonn",
"more"
] | 45 | 1 | 1 | [
"A001208",
"A001209",
"A001210",
"A001211",
"A001212",
"A001213",
"A001214",
"A001215",
"A001216",
"A005342",
"A005343",
"A005344",
"A014616",
"A053346",
"A053348",
"A075060",
"A084192",
"A084193",
"A196416"
] | [
"M3391",
"N1559"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001214.seq | 9ace806e6fd5ad23e58ec3fd363674cc |
A001215 | a(n) is the solution to the postage stamp problem with n denominations and 5 stamps. | [
"5",
"14",
"35",
"71",
"126",
"211",
"336",
"524",
"726",
"1016",
"1393",
"1871",
"2494",
"3196",
"4063",
"5113",
"6511",
"7949",
"9865",
"11589"
] | [
"nonn",
"more"
] | 45 | 1 | 1 | [
"A001208",
"A001209",
"A001210",
"A001211",
"A001212",
"A001213",
"A001214",
"A001215",
"A001216",
"A005342",
"A005343",
"A005344",
"A014616",
"A053346",
"A053348",
"A075060",
"A084192",
"A084193",
"A196416"
] | [
"M3845",
"N1706"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001215.seq | 083324724bccec8b9ebe089de9970d0a |
A001216 | a(n) = solution to the postage stamp problem with n denominations and 6 stamps. | [
"6",
"18",
"52",
"114",
"216",
"388",
"638",
"1007",
"1545",
"2287"
] | [
"nonn",
"more"
] | 37 | 1 | 1 | [
"A001208",
"A001209",
"A001210",
"A001211",
"A001212",
"A001213",
"A001214",
"A001215",
"A001216",
"A005342",
"A005343",
"A005344",
"A014616",
"A053346",
"A053348",
"A075060",
"A084192",
"A084193",
"A196416"
] | [
"M4120",
"N1831"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001216.seq | b395890a95c7fc74760145486b737170 |
A001217 | Sorted list of orders of Weyl groups of types A_n, B_n, D_n, E_n, F_4, G_2. | [
"1",
"2",
"4",
"6",
"8",
"12",
"24",
"48",
"120",
"192",
"384",
"720",
"1152",
"1920",
"3840",
"5040",
"23040",
"40320",
"46080",
"51840",
"322560",
"362880",
"645120",
"2903040",
"3628800",
"5160960",
"10321920",
"39916800",
"92897280",
"185794560",
"4790... | [
"nonn",
"easy",
"nice"
] | 20 | 1 | 2 | null | null | N. J. A. Sloane | 2025-05-17T06:09:19 | oeisdata/seq/A001/A001217.seq | 3f9c15b884cd34e9b89cda36b08df97a |
A001218 | a(n) = 3^n mod 100. | [
"1",
"3",
"9",
"27",
"81",
"43",
"29",
"87",
"61",
"83",
"49",
"47",
"41",
"23",
"69",
"7",
"21",
"63",
"89",
"67",
"1",
"3",
"9",
"27",
"81",
"43",
"29",
"87",
"61",
"83",
"49",
"47",
"41",
"23",
"69",
"7",
"21",
"63",
"89",
"67",
"1",... | [
"nonn",
"easy"
] | 31 | 0 | 2 | [
"A001148",
"A001218",
"A216096",
"A216097"
] | null | N. J. A. Sloane | 2025-08-08T08:33:57 | oeisdata/seq/A001/A001218.seq | 9cba3e99bbdd8534ddba5f690160b53b |
A001219 | Triangular numbers of form a(a+1)(a+2). | [
"0",
"6",
"120",
"210",
"990",
"185136",
"258474216"
] | [
"nonn",
"fini",
"full"
] | 22 | 1 | 2 | [
"A000217",
"A001219",
"A097571"
] | null | N. J. A. Sloane | 2025-02-16T08:32:22 | oeisdata/seq/A001/A001219.seq | d040dd26b8fab8b6eb8d075c627f3c28 |
A001220 | Wieferich primes: primes p such that p^2 divides 2^(p-1) - 1. | [
"1093",
"3511"
] | [
"nonn",
"hard",
"bref",
"nice",
"more"
] | 381 | 1 | 1 | [
"A001008",
"A001220",
"A001567",
"A002323",
"A007540",
"A014127",
"A039951",
"A045616",
"A049094",
"A077816",
"A088164",
"A090968",
"A111027",
"A123692",
"A123693",
"A126196",
"A126197",
"A128667",
"A128668",
"A128669",
"A178815",
"A178844",
"A178871",
"A178900",
"A21... | null | N. J. A. Sloane | 2025-12-15T20:06:51 | oeisdata/seq/A001/A001220.seq | 15083d790096622ddce336fdae9bfdfe |
A001221 | Number of distinct primes dividing n (also called omega(n)). | [
"0",
"1",
"1",
"1",
"1",
"2",
"1",
"1",
"1",
"2",
"1",
"2",
"1",
"2",
"2",
"1",
"1",
"2",
"1",
"2",
"2",
"2",
"1",
"2",
"1",
"2",
"1",
"2",
"1",
"3",
"1",
"1",
"2",
"2",
"2",
"2",
"1",
"2",
"2",
"2",
"1",
"3",
"1",
"2",
"2",
"... | [
"nonn",
"easy",
"nice",
"core"
] | 221 | 1 | 6 | [
"A000005",
"A000010",
"A001221",
"A001222",
"A005063",
"A005064",
"A005065",
"A008472",
"A008683",
"A013939",
"A033273",
"A034444",
"A046660",
"A069010",
"A069359",
"A087624",
"A091202",
"A091221",
"A125666",
"A143519",
"A144494",
"A156542",
"A156552",
"A158210",
"A28... | [
"M0056",
"N0019"
] | N. J. A. Sloane | 2025-12-29T15:37:08 | oeisdata/seq/A001/A001221.seq | 0fa69efed380b573cb3e461de03baa4b |
A001222 | Number of prime divisors of n counted with multiplicity (also called big omega of n, bigomega(n) or Omega(n)). | [
"0",
"1",
"1",
"2",
"1",
"2",
"1",
"3",
"2",
"2",
"1",
"3",
"1",
"2",
"2",
"4",
"1",
"3",
"1",
"3",
"2",
"2",
"1",
"4",
"2",
"2",
"3",
"3",
"1",
"3",
"1",
"5",
"2",
"2",
"2",
"4",
"1",
"2",
"2",
"4",
"1",
"3",
"1",
"3",
"3",
"... | [
"nonn",
"easy",
"nice",
"core"
] | 229 | 1 | 4 | [
"A000010",
"A000040",
"A000120",
"A001221",
"A001222",
"A001358",
"A008836",
"A014612",
"A014613",
"A014614",
"A020639",
"A022559",
"A027748",
"A046306",
"A046308",
"A046310",
"A046312",
"A046314",
"A046660",
"A066829",
"A069272",
"A069273",
"A069274",
"A069275",
"A06... | [
"M0094",
"N0031"
] | N. J. A. Sloane | 2025-11-05T15:21:40 | oeisdata/seq/A001/A001222.seq | b89fd358efcff5e45dd6b8b3a8df5e95 |
A001223 | Prime gaps: differences between consecutive primes. | [
"1",
"2",
"2",
"4",
"2",
"4",
"2",
"4",
"6",
"2",
"6",
"4",
"2",
"4",
"6",
"6",
"2",
"6",
"4",
"2",
"6",
"4",
"6",
"8",
"4",
"2",
"4",
"2",
"4",
"14",
"4",
"6",
"2",
"10",
"2",
"6",
"6",
"4",
"6",
"6",
"2",
"10",
"2",
"4",
"2",
... | [
"nonn",
"nice",
"easy",
"hear"
] | 353 | 1 | 2 | [
"A000040",
"A000230",
"A000720",
"A001223",
"A001248",
"A005250",
"A005669",
"A007921",
"A008347",
"A028334",
"A029707",
"A029709",
"A030173",
"A031131",
"A031165",
"A031166",
"A031167",
"A031168",
"A031169",
"A031170",
"A031171",
"A031172",
"A036263",
"A036274",
"A03... | [
"M0296",
"N0108"
] | N. J. A. Sloane | 2025-11-05T15:21:40 | oeisdata/seq/A001/A001223.seq | dbc5aaca24ef6ba04aca442bb8b07bff |
A001224 | If F(n) is the n-th Fibonacci number, then a(2n) = (F(2n+1) + F(n+2))/2 and a(2n+1) = (F(2n+2) + F(n+1))/2. | [
"1",
"2",
"2",
"4",
"5",
"9",
"12",
"21",
"30",
"51",
"76",
"127",
"195",
"322",
"504",
"826",
"1309",
"2135",
"3410",
"5545",
"8900",
"14445",
"23256",
"37701",
"60813",
"98514",
"159094",
"257608",
"416325",
"673933",
"1089648",
"1763581",
"2852242",... | [
"nonn",
"nice",
"easy"
] | 175 | 1 | 2 | [
"A000045",
"A001224",
"A060312",
"A068928",
"A102526"
] | [
"M0318",
"N0117"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001224.seq | da1404fe1e0a15988f0ad7ba931c1e8f |
A001225 | Number of consistent arcs in a tournament with n nodes. | [
"1",
"2",
"5",
"7",
"11",
"14",
"20",
"24",
"30",
"35",
"44",
"50"
] | [
"nonn",
"nice",
"hard",
"more"
] | 39 | 2 | 2 | [
"A001225",
"A003141"
] | [
"M1333",
"N0510"
] | N. J. A. Sloane | 2021-08-28T02:53:48 | oeisdata/seq/A001/A001225.seq | 63190b286c55fe0afd54d8ea96b17d22 |
A001226 | Lerch's function q_2(n) = (2^{phi(t)} - 1)/t where t = 2*n - 1. | [
"1",
"1",
"3",
"9",
"7",
"93",
"315",
"17",
"3855",
"13797",
"195",
"182361",
"41943",
"9709",
"9256395",
"34636833",
"31775",
"479349",
"1857283155",
"430185",
"26817356775",
"102280151421",
"372827",
"1497207322929",
"89756051247",
"84215045",
"84973577874915",
... | [
"nonn"
] | 21 | 1 | 3 | [
"A000010",
"A001226"
] | null | N. J. A. Sloane | 2017-12-19T02:23:04 | oeisdata/seq/A001/A001226.seq | 79bf6d93665eb3f477f352d3d197f6fd |
A001227 | Number of odd divisors of n. | [
"1",
"1",
"2",
"1",
"2",
"2",
"2",
"1",
"3",
"2",
"2",
"2",
"2",
"2",
"4",
"1",
"2",
"3",
"2",
"2",
"4",
"2",
"2",
"2",
"3",
"2",
"4",
"2",
"2",
"4",
"2",
"1",
"4",
"2",
"4",
"3",
"2",
"2",
"4",
"2",
"2",
"4",
"2",
"2",
"6",
"... | [
"nonn",
"easy",
"nice",
"mult",
"core"
] | 354 | 1 | 3 | [
"A000005",
"A000079",
"A000203",
"A000593",
"A001227",
"A001620",
"A002162",
"A010054",
"A038547",
"A050999",
"A051000",
"A051001",
"A051002",
"A051731",
"A053866",
"A054844",
"A055932",
"A060831",
"A066311",
"A069283",
"A069288",
"A073485",
"A073491",
"A107428",
"A10... | null | N. J. A. Sloane | 2025-11-26T15:59:31 | oeisdata/seq/A001/A001227.seq | 059ffb9e32096589fcfa88824eeef454 |
A001228 | Orders of sporadic simple groups. | [
"7920",
"95040",
"175560",
"443520",
"604800",
"10200960",
"44352000",
"50232960",
"244823040",
"898128000",
"4030387200",
"145926144000",
"448345497600",
"460815505920",
"495766656000",
"42305421312000",
"64561751654400",
"273030912000000",
"51765179004000000",
"90745943887872... | [
"nonn",
"fini",
"nice",
"full"
] | 26 | 1 | 1 | [
"A001034",
"A001228",
"A005180"
] | null | N. J. A. Sloane | 2025-02-16T08:32:23 | oeisdata/seq/A001/A001228.seq | 0215f8786b883430e22db59a5af14588 |
A001229 | Numbers k such that phi(sigma(k)) = k. | [
"1",
"2",
"8",
"12",
"128",
"240",
"720",
"6912",
"32768",
"142560",
"712800",
"1140480",
"1190400",
"3345408",
"3571200",
"5702400",
"14859936",
"29719872",
"50319360",
"118879488",
"2147483648",
"3889036800",
"4389396480",
"21946982400",
"47416320000",
"9217732608... | [
"nonn"
] | 72 | 1 | 2 | [
"A000010",
"A001229",
"A018784",
"A135240",
"A373435",
"A373453",
"A373454"
] | null | N. J. A. Sloane | 2025-11-05T15:21:40 | oeisdata/seq/A001/A001229.seq | a1c392f16f9a7b2ca6f00dbf2fd82804 |
A001230 | Number of undirected closed knight's tours on a 2n X 2n chessboard. | [
"0",
"0",
"9862",
"13267364410532"
] | [
"nonn",
"hard",
"more",
"nice",
"changed"
] | 70 | 1 | 3 | [
"A001230",
"A165134"
] | null | N. J. A. Sloane, Martin Loebbing (loebbing(AT)ls2.informatik.uni-dortmund.de), Brendan McKay | 2026-01-14T16:15:11 | oeisdata/seq/A001/A001230.seq | d3aa25855ec05bf59f6bef8f8e9ee479 |
A001231 | Number of nonisomorphic projective planes of order n. | [
"1",
"1",
"1",
"1",
"0",
"1",
"1",
"4",
"0"
] | [
"nonn",
"hard",
"more",
"nice"
] | 31 | 2 | 8 | null | null | N. J. A. Sloane | 2025-07-08T00:18:27 | oeisdata/seq/A001/A001231.seq | 1805061505bcfa2adf5f31abf8030ba6 |
A001232 | Numbers k such that 9*k = (k written backwards), k > 0. | [
"1089",
"10989",
"109989",
"1099989",
"10891089",
"10999989",
"108901089",
"109999989",
"1089001089",
"1098910989",
"1099999989",
"10890001089",
"10989010989",
"10999999989",
"108900001089",
"108910891089",
"109890010989",
"109989109989",
"109999999989",
"1089000001089",
"108... | [
"base",
"nonn",
"nice"
] | 122 | 1 | 1 | [
"A001232",
"A002275",
"A002283",
"A004086",
"A008918",
"A008919",
"A031877",
"A094707",
"A124074",
"A193434",
"A222814",
"A222815"
] | null | N. J. A. Sloane and Simon Plouffe | 2025-11-05T15:21:40 | oeisdata/seq/A001/A001232.seq | aed8413d9e9cb970be456af227b3547f |
A001233 | Unsigned Stirling numbers of first kind s(n,6). | [
"1",
"21",
"322",
"4536",
"63273",
"902055",
"13339535",
"206070150",
"3336118786",
"56663366760",
"1009672107080",
"18861567058880",
"369012649234384",
"7551527592063024",
"161429736530118960",
"3599979517947607200",
"83637381699544802976",
"2021687376910682741568",
"50779532534... | [
"nonn",
"easy"
] | 58 | 6 | 2 | [
"A000254",
"A000399",
"A000454",
"A000482",
"A001233",
"A001234",
"A008275",
"A243569",
"A243570"
] | [
"M5114",
"N2216"
] | N. J. A. Sloane | 2025-09-22T16:00:14 | oeisdata/seq/A001/A001233.seq | 3a8386eab91af90bcc053adb5be76179 |
A001234 | Unsigned Stirling numbers of the first kind s(n,7). | [
"1",
"28",
"546",
"9450",
"157773",
"2637558",
"44990231",
"790943153",
"14409322928",
"272803210680",
"5374523477960",
"110228466184200",
"2353125040549984",
"52260903362512720",
"1206647803780373360",
"28939583397335447760"
] | [
"nonn",
"easy"
] | 46 | 7 | 2 | [
"A000254",
"A000399",
"A000454",
"A000482",
"A001233",
"A001234",
"A008275",
"A243569",
"A243570"
] | [
"M5202",
"N2264"
] | N. J. A. Sloane | 2025-09-22T16:00:14 | oeisdata/seq/A001/A001234.seq | 986ac2ed98120d6eb6f18b632c0acc73 |
A001235 | Taxi-cab numbers: sums of 2 cubes in more than 1 way. | [
"1729",
"4104",
"13832",
"20683",
"32832",
"39312",
"40033",
"46683",
"64232",
"65728",
"110656",
"110808",
"134379",
"149389",
"165464",
"171288",
"195841",
"216027",
"216125",
"262656",
"314496",
"320264",
"327763",
"373464",
"402597",
"439101",
"443889",
"513... | [
"nonn",
"nice"
] | 143 | 1 | 1 | [
"A001235",
"A003325",
"A003825",
"A003826",
"A007692",
"A008917",
"A011541",
"A018786",
"A018787",
"A018850",
"A023050",
"A023051",
"A051167",
"A051347",
"A155057",
"A343708",
"A360619"
] | null | N. J. A. Sloane | 2025-11-05T15:21:40 | oeisdata/seq/A001/A001235.seq | 04ab313693d2c2fb48319d96d4d09c1b |
A001236 | Differences of reciprocals of unity. | [
"15",
"575",
"46760",
"6998824",
"1744835904",
"673781602752",
"381495483224064",
"303443622431870976",
"327643295527342080000",
"466962174913357393920000",
"858175477913267353681920000",
"1993920215002599923346309120000",
"5758788816015998806424467537920000"
] | [
"nonn"
] | 30 | 1 | 1 | [
"A000254",
"A000424",
"A001236",
"A001237",
"A001238",
"A008969"
] | [
"M4993",
"N2149"
] | N. J. A. Sloane | 2020-04-28T11:51:37 | oeisdata/seq/A001/A001236.seq | 5dfbe220cd4675946580dd5362c79b0a |
A001237 | Differences of reciprocals of unity. | [
"31",
"3661",
"1217776",
"929081776",
"1413470290176",
"3878864920694016",
"17810567950611972096",
"129089983180418186674176",
"1409795030885143760732160000",
"22335321387514981111936450560000",
"497400843208278958640564703068160000",
"15161356456130244705175927906904309760000"
] | [
"nonn"
] | 39 | 1 | 1 | [
"A001237",
"A008969"
] | [
"M5229",
"N2276"
] | N. J. A. Sloane | 2024-07-30T02:53:08 | oeisdata/seq/A001/A001237.seq | 61d9367d258e62c39573ee46504d43ae |
A001238 | Differences of reciprocals of unity. | [
"63",
"22631",
"30480800",
"117550462624",
"1083688832185344",
"21006340945438768128",
"778101042571221893382144",
"51150996584622542869024997376",
"5626686079269855254796985958400000",
"987233834003503822099304377378406400000"
] | [
"nonn"
] | 28 | 1 | 1 | [
"A001238",
"A008969"
] | [
"M5328",
"N2316"
] | N. J. A. Sloane | 2023-12-22T08:35:23 | oeisdata/seq/A001/A001238.seq | 2ac6807e4ad69b7b658dd574fbaf21ab |
A001239 | Numbers that are the sum of 3 nonnegative cubes in more than 1 way. | [
"216",
"251",
"344",
"729",
"855",
"1009",
"1072",
"1366",
"1457",
"1459",
"1520",
"1674",
"1728",
"1729",
"1730",
"1737",
"1756",
"1763",
"1793",
"1854",
"1945",
"2008",
"2072",
"2241",
"2414",
"2456",
"2458",
"2729",
"2736",
"2752",
"3060",
"3391",
"... | [
"nonn"
] | 31 | 1 | 1 | [
"A001235",
"A001239",
"A003998",
"A008917",
"A025396",
"A025447",
"A025456"
] | null | N. J. A. Sloane | 2022-05-21T13:59:22 | oeisdata/seq/A001/A001239.seq | d9cd5212575f3d65a5c3b59456680df3 |
A001240 | Expansion of 1/((1-2x)(1-3x)(1-6x)). | [
"1",
"11",
"85",
"575",
"3661",
"22631",
"137845",
"833375",
"5019421",
"30174551",
"181222405",
"1087861775",
"6528756781",
"39177307271",
"235078159765",
"1410511939775",
"8463200647741",
"50779591044791",
"304678708005925"
] | [
"nonn",
"easy",
"nice"
] | 61 | 1 | 2 | [
"A001240",
"A008969",
"A021029",
"A112492"
] | [
"M4798",
"N2049"
] | N. J. A. Sloane | 2022-04-13T13:25:15 | oeisdata/seq/A001/A001240.seq | 1212e64c6402288ad98592393ee602b2 |
A001241 | Differences of reciprocals of unity. | [
"1",
"50",
"1660",
"46760",
"1217776",
"30480800",
"747497920",
"18139003520",
"437786795776",
"10536798272000",
"253246254177280",
"6082300519393280",
"146028165842661376",
"3505313580591718400",
"84135194495708938240",
"2019336829962040279040"
] | [
"nonn",
"easy"
] | 33 | 1 | 2 | [
"A001241",
"A008969",
"A028037",
"A112492"
] | [
"M5301",
"N2305"
] | N. J. A. Sloane | 2023-06-25T02:31:54 | oeisdata/seq/A001/A001241.seq | 3371af9781f5578629b1e262e8913158 |
A001242 | Differences of reciprocals of unity. | [
"1",
"274",
"48076",
"6998824",
"929081776",
"117550462624",
"14500866102976",
"1765130436471424",
"213373597575314176",
"25700650466807540224",
"3089923562153380965376",
"371145495540181143169024",
"44558899569395347436056576",
"5348360831598738338465357824"
] | [
"nonn",
"easy"
] | 21 | 1 | 2 | [
"A001242",
"A008969",
"A103878",
"A112492"
] | [
"M5433",
"N2362"
] | N. J. A. Sloane | 2015-06-13T00:48:03 | oeisdata/seq/A001/A001242.seq | 50b96bb61cedad9b854c721ea2a7b7ca |
A001243 | Eulerian numbers (Euler's triangle: column k=7 of A008292, column k=6 of A173018). | [
"1",
"247",
"14608",
"455192",
"9738114",
"162512286",
"2275172004",
"27971176092",
"311387598411",
"3207483178157",
"31055652948388",
"285997074307300",
"2527925001876036",
"21598596303099900",
"179385804170146680"
] | [
"nonn",
"easy"
] | 59 | 7 | 2 | [
"A000012",
"A000460",
"A000498",
"A000505",
"A000514",
"A001243",
"A008292",
"A173018"
] | [
"M5422",
"N2355"
] | N. J. A. Sloane, Mira Bernstein, Robert G. Wilson v | 2024-12-30T17:03:17 | oeisdata/seq/A001/A001243.seq | bac01093eb804089f17c0afb511cfe31 |
A001244 | Eulerian numbers (Euler's triangle: column k=8 of A008292, column k=7 of A173018). | [
"1",
"502",
"47840",
"2203488",
"66318474",
"1505621508",
"27971176092",
"447538817472",
"6382798925475",
"83137223185370",
"1006709967915228",
"11485644635009424",
"124748182104463860",
"1300365805079109480",
"13093713503185076040"
] | [
"nonn",
"easy"
] | 71 | 8 | 2 | [
"A000012",
"A000460",
"A000498",
"A000505",
"A000514",
"A001243",
"A001244",
"A008292",
"A123125",
"A173018"
] | [
"M5457",
"N2366"
] | N. J. A. Sloane, Mira Bernstein, and Robert G. Wilson v | 2025-01-04T22:47:26 | oeisdata/seq/A001/A001244.seq | c21505717538b7daffd766c0652e161e |
A001245 | Numbers that are the sum of 4 cubes in more than 1 way. | [
"81",
"126",
"128",
"216",
"217",
"219",
"224",
"243",
"251",
"252",
"259",
"278",
"280",
"315",
"341",
"343",
"344",
"345",
"352",
"371",
"376",
"378",
"405",
"408",
"432",
"434",
"467",
"469",
"496",
"522",
"540",
"559",
"560",
"567",
"584",
"5... | [
"nonn"
] | 14 | 1 | 1 | [
"A001235",
"A001245",
"A004826"
] | null | N. J. A. Sloane | 2022-02-02T00:06:34 | oeisdata/seq/A001/A001245.seq | 59e5610f8c21890cedc4d2eb38ef5265 |
A001246 | Squares of Catalan numbers. | [
"1",
"1",
"4",
"25",
"196",
"1764",
"17424",
"184041",
"2044900",
"23639044",
"282105616",
"3455793796",
"43268992144",
"551900410000",
"7152629313600",
"93990019574025",
"1250164827828900",
"16807771574144100",
"228138727737690000",
"3123219182728976100",
"430876768882609764... | [
"nonn",
"easy",
"nice"
] | 123 | 0 | 3 | [
"A000108",
"A000356",
"A000891",
"A001246",
"A008828",
"A186264",
"A209805"
] | null | N. J. A. Sloane | 2025-11-20T14:41:51 | oeisdata/seq/A001/A001246.seq | 9b386f7b16b7d646212e8977e8a3d082 |
A001247 | Squares of Bell numbers. | [
"1",
"1",
"4",
"25",
"225",
"2704",
"41209",
"769129",
"17139600",
"447195609",
"13450200625",
"460457244900",
"17754399678409",
"764214897046969",
"36442551140059684",
"1912574337188517025",
"109833379421325769609",
"6866586647633870998416",
"465228769500062060333281"
] | [
"nonn",
"easy"
] | 36 | 0 | 3 | [
"A000110",
"A001247"
] | null | N. J. A. Sloane | 2025-11-05T15:21:40 | oeisdata/seq/A001/A001247.seq | ae03197730028a24e9f889b47e745e6a |
A001248 | Squares of primes. | [
"4",
"9",
"25",
"49",
"121",
"169",
"289",
"361",
"529",
"841",
"961",
"1369",
"1681",
"1849",
"2209",
"2809",
"3481",
"3721",
"4489",
"5041",
"5329",
"6241",
"6889",
"7921",
"9409",
"10201",
"10609",
"11449",
"11881",
"12769",
"16129",
"17161",
"18769... | [
"nonn",
"easy"
] | 225 | 1 | 1 | [
"A000005",
"A000040",
"A000430",
"A001248",
"A001358",
"A001694",
"A002033",
"A005408",
"A005722",
"A006254",
"A008864",
"A024450",
"A033273",
"A048272",
"A049001",
"A051709",
"A059956",
"A060800",
"A062799",
"A069482",
"A078898",
"A082020",
"A085548",
"A087112",
"A09... | null | N. J. A. Sloane | 2025-11-02T05:36:11 | oeisdata/seq/A001/A001248.seq | 706a3b61b8716fc5bc3b5d315be0961c |
A001249 | Squares of tetrahedral numbers: a(n) = binomial(n+3,n)^2. | [
"1",
"16",
"100",
"400",
"1225",
"3136",
"7056",
"14400",
"27225",
"48400",
"81796",
"132496",
"207025",
"313600",
"462400",
"665856",
"938961",
"1299600",
"1768900",
"2371600",
"3136441",
"4096576",
"5290000",
"6760000",
"8555625",
"10732176",
"13351716",
"1648... | [
"nonn",
"easy"
] | 86 | 0 | 2 | [
"A000290",
"A000292",
"A000579",
"A001249",
"A001303",
"A006542",
"A008459",
"A033455",
"A040977",
"A086020",
"A108674"
] | null | N. J. A. Sloane | 2024-11-09T17:28:24 | oeisdata/seq/A001/A001249.seq | 0c62a2ee7e6e7dbb4d669c1d01d62bb9 |
A001250 | Number of alternating permutations of order n. | [
"1",
"1",
"2",
"4",
"10",
"32",
"122",
"544",
"2770",
"15872",
"101042",
"707584",
"5405530",
"44736512",
"398721962",
"3807514624",
"38783024290",
"419730685952",
"4809759350882",
"58177770225664",
"740742376475050",
"9902996106248192",
"138697748786275802",
"203084777... | [
"nonn"
] | 162 | 0 | 3 | [
"A000041",
"A000111",
"A001250",
"A001251",
"A001252",
"A001253",
"A003242",
"A010026",
"A010094",
"A025047",
"A032020",
"A049774",
"A056986",
"A104345",
"A211318",
"A260786",
"A261962",
"A325534",
"A325535",
"A335452",
"A344614",
"A344615",
"A344652",
"A344653",
"A34... | [
"M1235",
"N0472"
] | N. J. A. Sloane | 2025-09-22T16:00:14 | oeisdata/seq/A001/A001250.seq | ff2058b895ca27204485beaf4b6fccef |
A001251 | Number of permutations of order n with the length of longest run equal to 3. | [
"0",
"0",
"2",
"12",
"70",
"442",
"3108",
"24216",
"208586",
"1972904",
"20373338",
"228346522",
"2763212980",
"35926266244",
"499676669254",
"7405014187564",
"116511984902094",
"1940073930857802",
"34087525861589564",
"630296344519286304",
"12235215845125112122",
"24878973... | [
"nonn"
] | 43 | 1 | 3 | [
"A001250",
"A001251",
"A001252",
"A001253",
"A010026",
"A211318"
] | [
"M2031",
"N0803"
] | N. J. A. Sloane | 2025-11-05T15:21:40 | oeisdata/seq/A001/A001251.seq | 370eeb5b3e1229236533c1e9148657cb |
A001252 | Number of permutations of order n with the length of longest run equal to 4. | [
"0",
"0",
"0",
"2",
"16",
"134",
"1164",
"10982",
"112354",
"1245676",
"14909340",
"191916532",
"2646100822",
"38932850396",
"609137502242",
"10101955358506",
"177053463254274",
"3270694371428814",
"63524155236581118",
"1294248082658393546",
"27604013493657933856",
"6151358... | [
"nonn"
] | 43 | 1 | 4 | [
"A001250",
"A001251",
"A001252",
"A001253",
"A010026",
"A211318"
] | [
"M2092",
"N0827"
] | N. J. A. Sloane | 2025-11-05T15:21:40 | oeisdata/seq/A001/A001252.seq | afc37f7910a75cc00c1c7f6139556b86 |
A001253 | Number of permutations of order n with the length of longest run equal to 5. | [
"0",
"0",
"0",
"0",
"2",
"20",
"198",
"2048",
"22468",
"264538",
"3340962",
"45173518",
"652209564",
"10024669626",
"163546399460",
"2823941647390",
"51468705947590",
"987671243816650",
"19909066390361346",
"420650676776338140",
"9297308938203169622",
"214562999510569012168... | [
"nonn"
] | 42 | 1 | 5 | [
"A001250",
"A001251",
"A001252",
"A001253",
"A010026",
"A211318"
] | [
"M2123",
"N0840"
] | N. J. A. Sloane | 2025-11-05T15:21:40 | oeisdata/seq/A001/A001253.seq | b2dc261df56f732d6b815e3c22e2ea1d |
A001254 | Squares of Lucas numbers. | [
"4",
"1",
"9",
"16",
"49",
"121",
"324",
"841",
"2209",
"5776",
"15129",
"39601",
"103684",
"271441",
"710649",
"1860496",
"4870849",
"12752041",
"33385284",
"87403801",
"228826129",
"599074576",
"1568397609",
"4106118241",
"10749957124",
"28143753121",
"736813022... | [
"nonn",
"easy"
] | 96 | 0 | 1 | [
"A000032",
"A000204",
"A001254",
"A001638",
"A005970",
"A006499",
"A007598",
"A075150",
"A079291",
"A103324"
] | null | N. J. A. Sloane | 2022-09-08T08:44:28 | oeisdata/seq/A001/A001254.seq | e6fde27c7523bead97ce6395068fc6f8 |
A001255 | Squares of partition numbers. | [
"1",
"1",
"4",
"9",
"25",
"49",
"121",
"225",
"484",
"900",
"1764",
"3136",
"5929",
"10201",
"18225",
"30976",
"53361",
"88209",
"148225",
"240100",
"393129",
"627264",
"1004004",
"1575025",
"2480625",
"3833764",
"5934096",
"9060100",
"13823524",
"20839225",... | [
"nonn",
"easy"
] | 37 | 0 | 3 | [
"A000041",
"A000290",
"A001255",
"A054440",
"A133042",
"A200089",
"A304990"
] | null | N. J. A. Sloane | 2025-04-24T06:29:19 | oeisdata/seq/A001/A001255.seq | 879810cacbf3afb7d1cfbcdaab9f3c23 |
A001256 | Squares of numbers of trees. | [
"1",
"1",
"1",
"1",
"4",
"9",
"36",
"121",
"529",
"2209",
"11236",
"55225",
"303601",
"1692601",
"9979281",
"59923081",
"373262400",
"2364779641",
"15343033689",
"101095382025",
"677435994225",
"4598901695025",
"31626631547536",
"219871778549476",
"1544481904210609",
... | [
"nonn"
] | 16 | 0 | 5 | [
"A000055",
"A001256"
] | null | N. J. A. Sloane | 2022-02-02T00:08:45 | oeisdata/seq/A001/A001256.seq | 290bf2bc9ea2e561cd14f16c2203e5ef |
A001257 | Squares of numbers of rooted trees. | [
"1",
"1",
"4",
"16",
"81",
"400",
"2304",
"13225",
"81796",
"516961",
"3392964",
"22714756",
"155900196",
"1087218729",
"7710771721",
"55404215161",
"403030713409",
"2962388303281",
"21983682632976",
"164512124707984",
"1240577449436224"
] | [
"nonn"
] | 11 | 0 | 3 | [
"A000081",
"A001257"
] | null | N. J. A. Sloane | 2022-02-02T00:08:04 | oeisdata/seq/A001/A001257.seq | a5268da0ef101b68556e866d92566d1b |
A001258 | Number of labeled n-node trees with unlabeled end-points. | [
"1",
"1",
"2",
"6",
"25",
"135",
"892",
"6937",
"61886",
"621956",
"6946471",
"85302935",
"1141820808",
"16540534553",
"257745010762",
"4298050731298",
"76356627952069",
"1439506369337319",
"28699241994332940",
"603229325513240569",
"13330768181611378558",
"3089678666714899... | [
"nonn",
"nice"
] | 32 | 2 | 3 | [
"A001258",
"A151880"
] | [
"M1678",
"N0660"
] | N. J. A. Sloane. More terms from N. J. A. Sloane, Jun 07 2012 | 2017-05-14T04:36:14 | oeisdata/seq/A001/A001258.seq | d8d3f683046ecdc78492ff4029f0009e |
A001259 | A sequence of sorted odd primes 3 = p_1 < p_2 < ... < p_m such that p_i-2 divides the product p_1*p_2*...*p_(i-1) of the earlier primes and each prime factor of p_i-1 is a prime factor of twice the product. | [
"3",
"5",
"7",
"17",
"19",
"37",
"97",
"113",
"257",
"401",
"487",
"631",
"971",
"1297",
"1801",
"19457",
"22051",
"28817",
"65537",
"157303",
"160001"
] | [
"nonn",
"fini",
"full"
] | 37 | 1 | 1 | [
"A001259",
"A007015",
"A342701"
] | [
"M2423",
"N0958"
] | N. J. A. Sloane | 2021-03-19T06:58:30 | oeisdata/seq/A001/A001259.seq | e63422691f71e33714487e50f8f07a57 |
A001260 | Number of permutations of length n with 4 consecutive ascending pairs. | [
"0",
"0",
"0",
"0",
"1",
"5",
"45",
"385",
"3710",
"38934",
"444990",
"5506710",
"73422855",
"1049946755",
"16035550531",
"260577696015",
"4489954146860",
"81781307674780",
"1570201107355980",
"31698434854748604",
"671260973394676605",
"14879618243581997745"
] | [
"nonn"
] | 43 | 1 | 6 | [
"A000166",
"A000255",
"A000274",
"A000313",
"A001260",
"A001261",
"A010027"
] | [
"M3999",
"N1657"
] | N. J. A. Sloane | 2020-05-09T15:11:53 | oeisdata/seq/A001/A001260.seq | 4fd220b9989b29a2c465621af2de4f40 |
A001261 | Number of permutations of length n with 5 consecutive ascending pairs. | [
"0",
"0",
"0",
"0",
"0",
"1",
"6",
"63",
"616",
"6678",
"77868",
"978978",
"13216104",
"190899423",
"2939850914",
"48106651593",
"833848627248",
"15265844099324",
"294412707629208",
"5966764207952724",
"126793739418994416",
"2819296088257641741",
"65470320271760790078"
] | [
"nonn"
] | 26 | 1 | 7 | [
"A000166",
"A000255",
"A000274",
"A000313",
"A001260",
"A001261",
"A010027"
] | [
"M4273",
"N1786"
] | N. J. A. Sloane | 2021-12-19T09:53:57 | oeisdata/seq/A001/A001261.seq | 8fc7fd9064bca0e35e591ae0da13012b |
A001262 | Strong pseudoprimes to base 2. | [
"2047",
"3277",
"4033",
"4681",
"8321",
"15841",
"29341",
"42799",
"49141",
"52633",
"65281",
"74665",
"80581",
"85489",
"88357",
"90751",
"104653",
"130561",
"196093",
"220729",
"233017",
"252601",
"253241",
"256999",
"271951",
"280601",
"314821",
"357761",
"... | [
"nonn",
"nice"
] | 102 | 1 | 1 | [
"A001262",
"A001567",
"A020229",
"A020231",
"A020233",
"A056915",
"A072276",
"A074773",
"A215568"
] | null | N. J. A. Sloane | 2025-11-13T13:41:34 | oeisdata/seq/A001/A001262.seq | 034ca7b212c38ac24cecfe727a288fa5 |
A001263 | Triangle of Narayana numbers T(n,k) = C(n-1,k-1)*C(n,k-1)/k with 1 <= k <= n, read by rows. Also called the Catalan triangle. | [
"1",
"1",
"1",
"1",
"3",
"1",
"1",
"6",
"6",
"1",
"1",
"10",
"20",
"10",
"1",
"1",
"15",
"50",
"50",
"15",
"1",
"1",
"21",
"105",
"175",
"105",
"21",
"1",
"1",
"28",
"196",
"490",
"490",
"196",
"28",
"1",
"1",
"36",
"336",
"1176",
"1764... | [
"nonn",
"easy",
"tabl",
"nice",
"look"
] | 748 | 1 | 5 | [
"A000081",
"A000108",
"A000217",
"A000372",
"A001263",
"A002083",
"A002378",
"A002415",
"A005043",
"A006542",
"A006857",
"A007318",
"A008459",
"A010790",
"A016098",
"A032027",
"A033282",
"A055277",
"A056932",
"A056939",
"A056940",
"A056941",
"A065329",
"A073345",
"A08... | null | N. J. A. Sloane | 2025-12-23T11:04:02 | oeisdata/seq/A001/A001263.seq | 0270fe8b83e66bfa130d15934f9e6439 |
A001264 | Final 2 digits of 4^n. | [
"1",
"4",
"16",
"64",
"56",
"24",
"96",
"84",
"36",
"44",
"76",
"4",
"16",
"64",
"56",
"24",
"96",
"84",
"36",
"44",
"76",
"4",
"16",
"64",
"56",
"24",
"96",
"84",
"36",
"44",
"76",
"4",
"16",
"64",
"56",
"24",
"96",
"84",
"36",
"44",
"... | [
"nonn",
"easy"
] | 21 | 0 | 2 | null | null | N. J. A. Sloane | 2022-09-08T08:44:29 | oeisdata/seq/A001/A001264.seq | 071c3acbf0736cb3f4020b837a0b7823 |
A001265 | Table T(n,k) in which n-th row lists prime factors of 2^n - 1 (n >= 2), with repetition. | [
"3",
"7",
"3",
"5",
"31",
"3",
"3",
"7",
"127",
"3",
"5",
"17",
"7",
"73",
"3",
"11",
"31",
"23",
"89",
"3",
"3",
"5",
"7",
"13",
"8191",
"3",
"43",
"127",
"7",
"31",
"151",
"3",
"5",
"17",
"257",
"131071",
"3",
"3",
"3",
"7",
"19",
"... | [
"nonn",
"tabf"
] | 51 | 2 | 1 | [
"A001265",
"A060443",
"A182590"
] | null | N. J. A. Sloane | 2025-02-16T08:32:23 | oeisdata/seq/A001/A001265.seq | 3457a69e57d22fa8944fddf592e9fba2 |
A001266 | One-half the number of permutations of length n without rising or falling successions. | [
"0",
"0",
"1",
"7",
"45",
"323",
"2621",
"23811",
"239653",
"2648395",
"31889517",
"415641779",
"5830753109",
"87601592187",
"1403439027805",
"23883728565283",
"430284458893701",
"8181419271349931",
"163730286973255373",
"3440164703027845395",
"75718273707281368117",
"17422... | [
"nonn"
] | 44 | 2 | 4 | [
"A001266",
"A002464",
"A010028",
"A086856"
] | [
"M4426",
"N1871"
] | N. J. A. Sloane | 2025-04-25T17:10:24 | oeisdata/seq/A001/A001266.seq | 182670cd0177a656c790b5edb1e4f0ac |
A001267 | One-half the number of permutations of length n with exactly 3 rising or falling successions. | [
"0",
"0",
"0",
"0",
"1",
"8",
"60",
"444",
"3599",
"32484",
"325322",
"3582600",
"43029621",
"559774736",
"7841128936",
"117668021988",
"1883347579515",
"32026067455084",
"576605574327174",
"10957672400252944",
"219190037987444577",
"4603645435776504120",
"101292568208941... | [
"nonn"
] | 24 | 0 | 6 | [
"A000130",
"A001267",
"A002464",
"A010028",
"A086852",
"A086854"
] | [
"M4550",
"N1934"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001267.seq | 40224650e0697ddc4607c868f1704c58 |
A001268 | One-half the number of permutations of length n with exactly 4 rising or falling successions. | [
"0",
"0",
"0",
"0",
"0",
"1",
"11",
"113",
"1099",
"11060",
"118484",
"1366134",
"16970322",
"226574211",
"3240161105",
"49453685911",
"802790789101",
"13815657556958",
"251309386257874",
"4818622686395380",
"97145520138758844",
"2054507019515346789",
"4548400697041522328... | [
"nonn"
] | 25 | 0 | 7 | [
"A000130",
"A001268",
"A002464",
"A010028",
"A086852",
"A086855"
] | [
"M4805",
"N2053"
] | N. J. A. Sloane | 2021-12-19T09:54:54 | oeisdata/seq/A001/A001268.seq | 2ddce77d699cd668980a9d3b2a7542b8 |
A001269 | Table T(n,k) in which n-th row lists prime factors of 2^n + 1 (n >= 0), with repetition. | [
"2",
"3",
"5",
"3",
"3",
"17",
"3",
"11",
"5",
"13",
"3",
"43",
"257",
"3",
"3",
"3",
"19",
"5",
"5",
"41",
"3",
"683",
"17",
"241",
"3",
"2731",
"5",
"29",
"113",
"3",
"3",
"11",
"331",
"65537",
"3",
"43691",
"5",
"13",
"37",
"109",
"3... | [
"nonn",
"tabf"
] | 36 | 0 | 1 | [
"A001269",
"A054992",
"A060444"
] | null | N. J. A. Sloane | 2024-02-29T23:08:14 | oeisdata/seq/A001/A001269.seq | 947e8d976625679ec72809d113599e7e |
A001270 | Table of prime factors of 10^n - 1 (with multiplicity). | [
"3",
"3",
"3",
"3",
"11",
"3",
"3",
"3",
"37",
"3",
"3",
"11",
"101",
"3",
"3",
"41",
"271",
"3",
"3",
"3",
"7",
"11",
"13",
"37",
"3",
"3",
"239",
"4649",
"3",
"3",
"11",
"73",
"101",
"137",
"3",
"3",
"3",
"3",
"37",
"333667",
"3",
"... | [
"nonn",
"tabf"
] | 26 | 1 | 1 | [
"A001270",
"A002283"
] | null | N. J. A. Sloane | 2023-05-23T22:59:24 | oeisdata/seq/A001/A001270.seq | a630ac49a0509aa69ee45a28d9d6e143 |
A001271 | Irregular table read by rows: row n lists prime factors of 10^n + 1, with multiplicity. | [
"2",
"11",
"101",
"7",
"11",
"13",
"73",
"137",
"11",
"9091",
"101",
"9901",
"11",
"909091",
"17",
"5882353",
"7",
"11",
"13",
"19",
"52579",
"101",
"3541",
"27961",
"11",
"11",
"23",
"4093",
"8779",
"73",
"137",
"99990001",
"11",
"859",
"105831304... | [
"nonn",
"tabf"
] | 47 | 0 | 1 | [
"A001271",
"A028416",
"A057934",
"A062397",
"A391444"
] | null | N. J. A. Sloane, revised Jul 13 2009 | 2025-12-10T06:08:47 | oeisdata/seq/A001/A001271.seq | 1a6e24c6e0c101da0844996c7175961c |
A001272 | Numbers k such that k! - (k-1)! + (k-2)! - (k-3)! + ... - (-1)^k*1! is prime. | [
"3",
"4",
"5",
"6",
"7",
"8",
"10",
"15",
"19",
"41",
"59",
"61",
"105",
"160",
"661",
"2653",
"3069",
"3943",
"4053",
"4998",
"8275",
"9158",
"11164",
"43592",
"59961"
] | [
"nonn",
"hard",
"more",
"nice",
"fini"
] | 71 | 1 | 1 | [
"A001272",
"A002981",
"A002982",
"A005165",
"A100289"
] | null | N. J. A. Sloane | 2025-02-16T08:32:23 | oeisdata/seq/A001/A001272.seq | d341568670a77961ad39ceb465b5c584 |
A001273 | Smallest number that takes n steps to reach 1 under iteration of sum-of-squares-of-digits map (= smallest "happy number" of height n). | [
"1",
"10",
"13",
"23",
"19",
"7",
"356",
"78999"
] | [
"nonn",
"base"
] | 66 | 0 | 2 | [
"A001273",
"A003132",
"A007770",
"A018785",
"A176762"
] | null | N. J. A. Sloane | 2025-11-05T15:21:40 | oeisdata/seq/A001/A001273.seq | 183a93ef995c223784b5e14d31db63c6 |
A001274 | Numbers k such that phi(k) = phi(k+1). | [
"1",
"3",
"15",
"104",
"164",
"194",
"255",
"495",
"584",
"975",
"2204",
"2625",
"2834",
"3255",
"3705",
"5186",
"5187",
"10604",
"11715",
"13365",
"18315",
"22935",
"25545",
"32864",
"38804",
"39524",
"46215",
"48704",
"49215",
"49335",
"56864",
"57584"... | [
"nonn",
"easy",
"nice"
] | 162 | 1 | 2 | [
"A000010",
"A001274",
"A001494",
"A003275",
"A003276",
"A007015",
"A051953",
"A179186",
"A179187",
"A179188",
"A179189",
"A179202",
"A217139",
"A300285"
] | [
"M2999",
"N1215"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001274.seq | e998f504dd64d8438c19e1d61a2e78e4 |
A001275 | Smallest prime p such that the product of q/(q-1) over the primes from prime(n) to p is greater than 2. | [
"3",
"7",
"23",
"61",
"127",
"199",
"337",
"479",
"677",
"937",
"1193",
"1511",
"1871",
"2267",
"2707",
"3251",
"3769",
"4349",
"5009",
"5711",
"6451",
"7321",
"8231",
"9173",
"10151",
"11197",
"12343",
"13487",
"14779",
"16097",
"17599",
"19087",
"205... | [
"nonn"
] | 21 | 1 | 1 | [
"A001275",
"A001276"
] | [
"M4378",
"N1842"
] | N. J. A. Sloane | 2019-07-12T19:04:14 | oeisdata/seq/A001/A001275.seq | d3a0f00ae1e31d34ecb497e40c6ffd36 |
A001276 | Smallest k such that the product of q/(q-1) over the primes from prime(n) to prime(n+k-1) is greater than 2. | [
"2",
"3",
"7",
"15",
"27",
"41",
"62",
"85",
"115",
"150",
"186",
"229",
"274",
"323",
"380",
"443",
"509",
"577",
"653",
"733",
"818",
"912",
"1010",
"1114",
"1222",
"1331",
"1448",
"1572",
"1704",
"1845",
"1994",
"2138",
"2289",
"2445",
"2609",
... | [
"nonn"
] | 34 | 1 | 1 | [
"A001275",
"A001276",
"A005101",
"A108227"
] | [
"M2650",
"N1057"
] | N. J. A. Sloane | 2021-04-14T11:07:05 | oeisdata/seq/A001/A001276.seq | 08f8cdd5c2eab9e447e9daa05bde8d7a |
A001277 | Number of permutations of length n by rises. | [
"1",
"3",
"12",
"56",
"321",
"2175",
"17008",
"150504",
"1485465",
"16170035",
"192384876",
"2483177808",
"34554278857",
"515620794591",
"8212685046336",
"139062777326000",
"2494364438359953",
"47245095998005059",
"942259727190907180",
"19737566982241851720",
"433234326593362... | [
"nonn"
] | 23 | 2 | 2 | [
"A001277",
"A173184"
] | [
"M2928",
"N1176"
] | N. J. A. Sloane | 2022-07-01T06:40:58 | oeisdata/seq/A001/A001277.seq | 1a788bef3c3c571db53eb5009d1fd1d6 |
A001278 | Number of permutations of length n by rises. | [
"1",
"11",
"87",
"693",
"5934",
"55674",
"572650",
"6429470",
"78366855",
"1031378445",
"14583751161",
"220562730171",
"3553474061452",
"60765835154948",
"1099353888345924",
"20980355229808524",
"421242574828254525",
"8876636475162819615",
"195887449298481357835",
"451786585823... | [
"nonn"
] | 17 | 4 | 2 | null | [
"M4799",
"N2050"
] | N. J. A. Sloane | 2022-07-01T06:46:07 | oeisdata/seq/A001/A001278.seq | bea140b84d8a5e896969a6423f58901c |
A001279 | Number of permutations of length n by rises. | [
"3",
"53",
"680",
"8064",
"96370",
"1200070",
"15778800",
"220047400",
"3257228485",
"51125192475",
"849388162448",
"14905775547488",
"275697902983860",
"5362979000259804",
"109488815508733440",
"2341353038132316240",
"52346701837709016375",
"1221458048752142672625",
"29697803502... | [
"nonn"
] | 16 | 6 | 1 | null | [
"M3159",
"N1279"
] | N. J. A. Sloane | 2022-07-01T06:50:22 | oeisdata/seq/A001/A001279.seq | 0cddbe9d787d6a5674bb1672e7087e08 |
A001280 | Number of permutations of length n by rises. | [
"11",
"309",
"5805",
"95575",
"1516785",
"24206055",
"396475975",
"6733084365",
"119143997490",
"2201649739310",
"42514526708766",
"857750898213594",
"18068801884373310",
"397038791150060850",
"9090755207499817170",
"216635190303090215910"
] | [
"nonn"
] | 16 | 8 | 1 | null | [
"M4811",
"N2058"
] | N. J. A. Sloane | 2022-07-01T07:30:34 | oeisdata/seq/A001/A001280.seq | a0bad1e0a1fe891ae1643a05ed1e13cb |
A001281 | Image of n under the map n->n/2 if n even, n->3n-1 if n odd. | [
"0",
"2",
"1",
"8",
"2",
"14",
"3",
"20",
"4",
"26",
"5",
"32",
"6",
"38",
"7",
"44",
"8",
"50",
"9",
"56",
"10",
"62",
"11",
"68",
"12",
"74",
"13",
"80",
"14",
"86",
"15",
"92",
"16",
"98",
"17",
"104",
"18",
"110",
"19",
"116",
"20",... | [
"nonn",
"easy"
] | 24 | 0 | 2 | [
"A001281",
"A006370",
"A006577",
"A037082",
"A037084",
"A039500",
"A039505",
"A135727",
"A135730"
] | null | N. J. A. Sloane | 2022-10-21T22:07:49 | oeisdata/seq/A001/A001281.seq | 353a639557a9d0ffb1330cb9e4692ad8 |
A001282 | Number of permutations of length n by rises. | [
"17",
"259",
"2770",
"27978",
"294602",
"3331790",
"40682144",
"535206440",
"7557750635",
"114101726625",
"1834757172082",
"31313852523634",
"565434670633580",
"10771030900532868",
"215881317066455232",
"4541623615098815280"
] | [
"nonn"
] | 14 | 6 | 1 | [
"A001282",
"A010030"
] | [
"M5047",
"N2181"
] | N. J. A. Sloane | 2022-02-03T00:31:44 | oeisdata/seq/A001/A001282.seq | eeda7c16414f4e1dc4425a6e82c75065 |
A001283 | Triangle read by rows, in which row n consists of n(n+m) for m = 1 .. n-1. | [
"6",
"12",
"15",
"20",
"24",
"28",
"30",
"35",
"40",
"45",
"42",
"48",
"54",
"60",
"66",
"56",
"63",
"70",
"77",
"84",
"91",
"72",
"80",
"88",
"96",
"104",
"112",
"120",
"90",
"99",
"108",
"117",
"126",
"135",
"144",
"153",
"110",
"120",
"1... | [
"nonn",
"easy",
"tabl"
] | 24 | 2 | 1 | [
"A001283",
"A003991",
"A033581",
"A063929",
"A063930",
"A085788"
] | null | N. J. A. Sloane | 2022-02-03T00:32:10 | oeisdata/seq/A001/A001283.seq | f88c9eeaa817227e046e2747a031ded1 |
A001284 | Numbers of form m*k with m+1 <= k <= 2m-1. | [
"6",
"12",
"15",
"20",
"24",
"28",
"30",
"35",
"40",
"42",
"45",
"48",
"54",
"56",
"60",
"63",
"66",
"70",
"72",
"77",
"80",
"84",
"88",
"90",
"91",
"96",
"99",
"104",
"108",
"110",
"112",
"117",
"120",
"126",
"130",
"132",
"135",
"140",
"1... | [
"nonn",
"easy"
] | 23 | 1 | 1 | [
"A001284",
"A005279"
] | null | N. J. A. Sloane | 2025-02-11T20:33:39 | oeisdata/seq/A001/A001284.seq | af0fc2ca7858e30123e450567c3a2d8f |
A001285 | Thue-Morse sequence: let A_k denote the first 2^k terms; then A_0 = 1 and for k >= 0, A_{k+1} = A_k B_k, where B_k is obtained from A_k by interchanging 1's and 2's. | [
"1",
"2",
"2",
"1",
"2",
"1",
"1",
"2",
"2",
"1",
"1",
"2",
"1",
"2",
"2",
"1",
"2",
"1",
"1",
"2",
"1",
"2",
"2",
"1",
"1",
"2",
"2",
"1",
"2",
"1",
"1",
"2",
"2",
"1",
"1",
"2",
"1",
"2",
"2",
"1",
"1",
"2",
"2",
"1",
"2",
"... | [
"nonn",
"easy",
"core",
"nice"
] | 137 | 0 | 2 | [
"A001285",
"A003159",
"A010059",
"A010060",
"A026430",
"A026465",
"A029885",
"A161175",
"A225186",
"A230958"
] | [
"M0193",
"N0071"
] | N. J. A. Sloane | 2025-11-05T15:21:40 | oeisdata/seq/A001/A001285.seq | f193d9fe447c1258c0046feb03a79c4d |
A001286 | Lah numbers: a(n) = (n-1)*n!/2. | [
"1",
"6",
"36",
"240",
"1800",
"15120",
"141120",
"1451520",
"16329600",
"199584000",
"2634508800",
"37362124800",
"566658892800",
"9153720576000",
"156920924160000",
"2845499424768000",
"54420176498688000",
"1094805903679488000",
"23112569077678080000",
"510909421717094400000"... | [
"nonn",
"easy",
"nice"
] | 182 | 2 | 2 | [
"A000110",
"A000111",
"A001113",
"A001286",
"A001620",
"A001710",
"A002868",
"A008292",
"A008297",
"A019538",
"A051683",
"A052609",
"A053495",
"A060570",
"A060608",
"A060612",
"A060638",
"A062119",
"A075181",
"A091725",
"A099285",
"A111596",
"A135218",
"A213168",
"A27... | [
"M4225",
"N1766"
] | N. J. A. Sloane | 2025-11-19T11:33:15 | oeisdata/seq/A001/A001286.seq | 00e2d636f5fb7037e0fd21b426175ff4 |
A001287 | a(n) = binomial coefficient C(n,10). | [
"1",
"11",
"66",
"286",
"1001",
"3003",
"8008",
"19448",
"43758",
"92378",
"184756",
"352716",
"646646",
"1144066",
"1961256",
"3268760",
"5311735",
"8436285",
"13123110",
"20030010",
"30045015",
"44352165",
"64512240",
"92561040",
"131128140",
"183579396",
"25418... | [
"nonn",
"easy"
] | 100 | 10 | 2 | [
"A001287",
"A001787",
"A110555",
"A242091"
] | [
"M4794",
"N2046"
] | N. J. A. Sloane | 2025-11-05T15:21:40 | oeisdata/seq/A001/A001287.seq | 88b4df3922b78f51393bebd261ad8898 |
A001288 | a(n) = binomial(n,11). | [
"1",
"12",
"78",
"364",
"1365",
"4368",
"12376",
"31824",
"75582",
"167960",
"352716",
"705432",
"1352078",
"2496144",
"4457400",
"7726160",
"13037895",
"21474180",
"34597290",
"54627300",
"84672315",
"129024480",
"193536720",
"286097760",
"417225900",
"600805296",
... | [
"nonn",
"easy"
] | 77 | 11 | 2 | [
"A001288",
"A001787",
"A110555",
"A242091"
] | [
"M4850",
"N2073"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001288.seq | ac77cb8b7a7f18e5fbe3024aec2a5ffa |
A001289 | Number of equivalence classes of Boolean functions modulo linear functions. | [
"1",
"2",
"3",
"8",
"48",
"150357",
"63379147320777408548"
] | [
"nonn",
"hard",
"more",
"nice"
] | 18 | 1 | 2 | [
"A001289",
"A109003"
] | null | N. J. A. Sloane | 2025-07-08T00:18:32 | oeisdata/seq/A001/A001289.seq | 8e4591ca4928d1414504452d6e7d13d4 |
A001290 | Erroneous version of A028368. | [
"192",
"21504",
"10321924"
] | [
"dead"
] | 23 | 2 | 1 | null | null | null | 2025-07-14T10:13:55 | oeisdata/seq/A001/A001290.seq | 80c71d9f777f6fe36cc43a7335363540 |
A001291 | Number of conjugacy classes in Restricted Affine Group on n variables. | [
"13",
"28",
"62",
"124"
] | [
"nonn",
"more"
] | 8 | 2 | 1 | null | null | N. J. A. Sloane | 2022-02-03T00:32:37 | oeisdata/seq/A001/A001291.seq | ab6b30d5909fa061351255f4d006937c |
A001292 | Concatenations of cyclic permutations of initial positive integers. | [
"1",
"12",
"21",
"123",
"231",
"312",
"1234",
"2341",
"3412",
"4123",
"12345",
"23451",
"34512",
"45123",
"51234",
"123456",
"234561",
"345612",
"456123",
"561234",
"612345",
"1234567",
"2345671",
"3456712",
"4567123",
"5671234",
"6712345",
"7123456"
] | [
"nonn",
"base"
] | 88 | 1 | 2 | [
"A001292",
"A093771",
"A134804",
"A352991"
] | null | R. Muller | 2025-10-24T19:50:39 | oeisdata/seq/A001/A001292.seq | f7034868a1a7b154f917e3ba0f69e6dd |
A001293 | Leech triangle: k-th number (0 <= k <= n) in n-th row (0 <= n) is number of octads in S(5,8,24) containing k given points and missing n-k given points. | [
"759",
"506",
"253",
"330",
"176",
"77",
"210",
"120",
"56",
"21",
"130",
"80",
"40",
"16",
"5",
"78",
"52",
"28",
"12",
"4",
"1",
"46",
"32",
"20",
"8",
"4",
"0",
"1",
"30",
"16",
"16",
"4",
"4",
"0",
"0",
"1",
"30",
"0",
"16",
"0",
"4... | [
"nonn",
"tabl",
"fini",
"full",
"nice"
] | 14 | 0 | 1 | null | null | N. J. A. Sloane | 2022-01-29T02:08:05 | oeisdata/seq/A001/A001293.seq | 072e6dfe049d0a75eaf8f3c87bb387fc |
A001294 | Triangle in which k-th number (0<=k<=n) in n-th row (0<=n) is number of dodecads in Golay code G_24 containing k given points and missing n-k given points. | [
"2576",
"1288",
"1288",
"616",
"672",
"616",
"280",
"336",
"336",
"280",
"120",
"160",
"176",
"160",
"120",
"48",
"72",
"88",
"88",
"72",
"48",
"16",
"32",
"40",
"48",
"40",
"32",
"16",
"0",
"16",
"16",
"24",
"24",
"16",
"16",
"0",
"0",
"0",
... | [
"nonn",
"tabl",
"fini",
"full",
"nice"
] | 13 | 0 | 1 | null | null | N. J. A. Sloane | 2022-01-29T12:16:56 | oeisdata/seq/A001/A001294.seq | 0c53de616c4b3c0a19d406f68440c553 |
A001295 | Triangle in which k-th number (0<=k<=n) in n-th row (0<=n) is number of hexads in S(5,6,12) containing k given points and missing n-k given points. | [
"132",
"66",
"66",
"30",
"36",
"30",
"12",
"18",
"18",
"12",
"4",
"8",
"10",
"8",
"4",
"1",
"3",
"5",
"5",
"3",
"1",
"1",
"0",
"3",
"2",
"3",
"0",
"1"
] | [
"nonn",
"tabl",
"fini",
"full"
] | 11 | 0 | 1 | null | null | N. J. A. Sloane | 2022-02-03T00:32:52 | oeisdata/seq/A001/A001295.seq | 974326f9842a50911ab02016be77d296 |
A001296 | 4-dimensional pyramidal numbers: a(n) = (3*n+1)*binomial(n+2, 3)/4. Also Stirling2(n+2, n). | [
"0",
"1",
"7",
"25",
"65",
"140",
"266",
"462",
"750",
"1155",
"1705",
"2431",
"3367",
"4550",
"6020",
"7820",
"9996",
"12597",
"15675",
"19285",
"23485",
"28336",
"33902",
"40250",
"47450",
"55575",
"64701",
"74907",
"86275",
"98890",
"112840",
"128216"... | [
"nonn",
"easy",
"nice"
] | 208 | 0 | 3 | [
"A000217",
"A000326",
"A000914",
"A001296",
"A001297",
"A001298",
"A002411",
"A008277",
"A008517",
"A034261",
"A093560",
"A094262",
"A220212",
"A241765",
"A254142"
] | [
"M4385",
"N1845"
] | N. J. A. Sloane | 2025-11-05T15:21:40 | oeisdata/seq/A001/A001296.seq | 9826da0739b2ede54e95c8ce8b9fbf9e |
A001297 | Stirling numbers of the second kind S(n+3, n). | [
"0",
"1",
"15",
"90",
"350",
"1050",
"2646",
"5880",
"11880",
"22275",
"39325",
"66066",
"106470",
"165620",
"249900",
"367200",
"527136",
"741285",
"1023435",
"1389850",
"1859550",
"2454606",
"3200450",
"4126200",
"5265000",
"6654375",
"8336601",
"10359090",
... | [
"nonn",
"easy"
] | 107 | 0 | 3 | [
"A001296",
"A001297",
"A001298",
"A001303",
"A008277",
"A008517",
"A048993",
"A062196",
"A094262"
] | [
"M4974",
"N2136"
] | N. J. A. Sloane | 2025-09-22T16:00:15 | oeisdata/seq/A001/A001297.seq | eeca040537f4f2c344c971aae561c6fd |
A001298 | Stirling numbers of the second kind S(n+4, n). | [
"0",
"1",
"31",
"301",
"1701",
"6951",
"22827",
"63987",
"159027",
"359502",
"752752",
"1479478",
"2757118",
"4910178",
"8408778",
"13916778",
"22350954",
"34952799",
"53374629",
"79781779",
"116972779",
"168519505",
"238929405",
"333832005",
"460192005",
"626551380... | [
"nonn",
"easy"
] | 87 | 0 | 3 | [
"A000915",
"A001296",
"A001297",
"A001298",
"A008277",
"A008517",
"A094262"
] | [
"M5222",
"N2272"
] | N. J. A. Sloane | 2025-09-22T16:00:15 | oeisdata/seq/A001/A001298.seq | 67a630f1997ce0c55ad42b2a7a7774bc |
A001299 | Number of ways of making change for n cents using coins of 1, 5, 10, 25 cents. | [
"1",
"1",
"1",
"1",
"1",
"2",
"2",
"2",
"2",
"2",
"4",
"4",
"4",
"4",
"4",
"6",
"6",
"6",
"6",
"6",
"9",
"9",
"9",
"9",
"9",
"13",
"13",
"13",
"13",
"13",
"18",
"18",
"18",
"18",
"18",
"24",
"24",
"24",
"24",
"24",
"31",
"31",
"31",... | [
"nonn",
"easy"
] | 55 | 0 | 6 | [
"A000008",
"A001299",
"A001300",
"A169718"
] | null | N. J. A. Sloane, Mar 15 1996 | 2025-11-10T21:50:37 | oeisdata/seq/A001/A001299.seq | c3ef8b745a249b382c80a7489119df07 |
A001300 | Number of ways of making change for n cents using coins of 1, 5, 10, 25, 50 cents. | [
"1",
"1",
"1",
"1",
"1",
"2",
"2",
"2",
"2",
"2",
"4",
"4",
"4",
"4",
"4",
"6",
"6",
"6",
"6",
"6",
"9",
"9",
"9",
"9",
"9",
"13",
"13",
"13",
"13",
"13",
"18",
"18",
"18",
"18",
"18",
"24",
"24",
"24",
"24",
"24",
"31",
"31",
"31",... | [
"nonn",
"easy"
] | 40 | 0 | 6 | [
"A000008",
"A001299",
"A001300",
"A169718"
] | null | N. J. A. Sloane, Mar 15 1996 | 2017-04-18T07:02:35 | oeisdata/seq/A001/A001300.seq | 1af5aac3a5ea0eb15047cd3b3422e1b1 |
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