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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
A001101 | Moran numbers: k such that k/(sum of digits of k) is prime. | [
"18",
"21",
"27",
"42",
"45",
"63",
"84",
"111",
"114",
"117",
"133",
"152",
"153",
"156",
"171",
"190",
"195",
"198",
"201",
"207",
"209",
"222",
"228",
"247",
"261",
"266",
"285",
"333",
"370",
"372",
"399",
"402",
"407",
"423",
"444",
"465",
... | [
"nonn",
"base",
"nice"
] | 65 | 1 | 1 | [
"A001101",
"A005349",
"A007953",
"A010051",
"A062339",
"A085775",
"A108780",
"A130338"
] | null | Bill Moran (moran1(AT)llnl.gov) | 2025-05-14T01:12:34 | oeisdata/seq/A001/A001101.seq | b1d0059ce52046ec8c9010ee8c73103b |
A001102 | Numbers k such that k / (sum of digits of k) is a square. | [
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"12",
"24",
"36",
"48",
"81",
"100",
"144",
"150",
"192",
"200",
"225",
"288",
"300",
"320",
"324",
"375",
"400",
"441",
"500",
"512",
"600",
"640",
"648",
"700",
"704",
"735",
"800",
"832",
"882",... | [
"nonn",
"base",
"nice"
] | 29 | 1 | 2 | [
"A001102",
"A005349",
"A028839"
] | null | N. J. A. Sloane, Bill Moran (moran1(AT)llnl.gov) | 2022-09-08T08:44:28 | oeisdata/seq/A001/A001102.seq | f6e05ce1a14ce64aa91ef64b8f56be94 |
A001103 | Numbers k such that (k / product of digits of k) is 1 or a prime. | [
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"11",
"15",
"24",
"36",
"115",
"175",
"212",
"624",
"735",
"816",
"1115",
"1184",
"1197",
"1416",
"2144",
"3171",
"3276",
"3915",
"6624",
"7119",
"8832",
"9612",
"11133",
"11212",
"11331",
"12128",
"12... | [
"nonn",
"base",
"nice"
] | 46 | 1 | 2 | [
"A001103",
"A007602",
"A007954",
"A010051",
"A052382",
"A066577",
"A188642"
] | null | N. J. A. Sloane, Bill Moran (moran1(AT)llnl.gov) | 2024-03-30T15:37:01 | oeisdata/seq/A001/A001103.seq | 575ca818814a594bb2e25d23b48463bb |
A001104 | Numbers n such that n / product of digits of n is a square. | [
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"135",
"144",
"384",
"1575",
"1715",
"6144",
"6912",
"11664",
"14112",
"16224",
"18816",
"23328",
"26136",
"31212",
"41616",
"82944",
"83232",
"93312",
"131424",
"131712",
"186624",
"248832",
"371112",
"1168... | [
"nonn",
"base"
] | 12 | 1 | 2 | null | null | N. J. A. Sloane, Bill Moran (moran1(AT)llnl.gov) | 2019-05-09T09:21:06 | oeisdata/seq/A001/A001104.seq | 9ea88c131b33dc0d3daf2332406bc753 |
A001105 | a(n) = 2*n^2. | [
"0",
"2",
"8",
"18",
"32",
"50",
"72",
"98",
"128",
"162",
"200",
"242",
"288",
"338",
"392",
"450",
"512",
"578",
"648",
"722",
"800",
"882",
"968",
"1058",
"1152",
"1250",
"1352",
"1458",
"1568",
"1682",
"1800",
"1922",
"2048",
"2178",
"2312",
... | [
"nonn",
"easy"
] | 411 | 0 | 2 | [
"A000217",
"A000290",
"A001105",
"A002061",
"A002266",
"A006331",
"A016742",
"A028982",
"A028983",
"A056106",
"A058331",
"A077591",
"A116471",
"A139098",
"A165900",
"A183300",
"A194715",
"A226488",
"A245508",
"A247375",
"A251599",
"A290391",
"A290392"
] | null | Bernd.Walter(AT)frankfurt.netsurf.de | 2025-12-30T03:41:48 | oeisdata/seq/A001/A001105.seq | 648a7b5bdfe2e658af5d9326dfc6f628 |
A001106 | 9-gonal (or enneagonal or nonagonal) numbers: a(n) = n*(7*n-5)/2. | [
"0",
"1",
"9",
"24",
"46",
"75",
"111",
"154",
"204",
"261",
"325",
"396",
"474",
"559",
"651",
"750",
"856",
"969",
"1089",
"1216",
"1350",
"1491",
"1639",
"1794",
"1956",
"2125",
"2301",
"2484",
"2674",
"2871",
"3075",
"3286",
"3504",
"3729",
"39... | [
"nonn",
"easy",
"nice"
] | 189 | 0 | 3 | [
"A001106",
"A016993",
"A057655",
"A069099",
"A093564",
"A131875",
"A244646"
] | [
"M4604"
] | N. J. A. Sloane | 2025-11-26T15:59:31 | oeisdata/seq/A001/A001106.seq | 5145ee321ee5e05361b6ad668ced83c9 |
A001107 | 10-gonal (or decagonal) numbers: a(n) = n*(4*n-3). | [
"0",
"1",
"10",
"27",
"52",
"85",
"126",
"175",
"232",
"297",
"370",
"451",
"540",
"637",
"742",
"855",
"976",
"1105",
"1242",
"1387",
"1540",
"1701",
"1870",
"2047",
"2232",
"2425",
"2626",
"2835",
"3052",
"3277",
"3510",
"3751",
"4000",
"4257",
"... | [
"nonn",
"easy",
"nice"
] | 204 | 0 | 3 | [
"A000217",
"A000290",
"A000384",
"A001107",
"A002061",
"A002378",
"A002620",
"A002939",
"A002943",
"A003215",
"A007585",
"A007742",
"A014105",
"A016742",
"A016754",
"A017077",
"A028994",
"A033951",
"A033952",
"A033953",
"A033954",
"A033988",
"A033989",
"A033990",
"A03... | [
"M4690"
] | N. J. A. Sloane | 2025-09-15T13:53:59 | oeisdata/seq/A001/A001107.seq | 3b6c13258d5f9ec904eb4f55fa1d9ce4 |
A001108 | a(n)-th triangular number is a square: a(n+1) = 6*a(n) - a(n-1) + 2, with a(0) = 0, a(1) = 1. | [
"0",
"1",
"8",
"49",
"288",
"1681",
"9800",
"57121",
"332928",
"1940449",
"11309768",
"65918161",
"384199200",
"2239277041",
"13051463048",
"76069501249",
"443365544448",
"2584123765441",
"15061377048200",
"87784138523761",
"511643454094368",
"2982076586042449",
"17380816... | [
"nonn",
"easy",
"nice"
] | 306 | 0 | 3 | [
"A000129",
"A000203",
"A000217",
"A000290",
"A001108",
"A001109",
"A001110",
"A001652",
"A002315",
"A005319",
"A007913",
"A072221",
"A084301",
"A115598"
] | [
"M4536",
"N1924"
] | N. J. A. Sloane | 2025-11-26T15:59:31 | oeisdata/seq/A001/A001108.seq | ca6e570fbb5b793ffccedad57524543d |
A001109 | a(n)^2 is a triangular number: a(n) = 6*a(n-1) - a(n-2) with a(0)=0, a(1)=1. | [
"0",
"1",
"6",
"35",
"204",
"1189",
"6930",
"40391",
"235416",
"1372105",
"7997214",
"46611179",
"271669860",
"1583407981",
"9228778026",
"53789260175",
"313506783024",
"1827251437969",
"10650001844790",
"62072759630771",
"361786555939836",
"2108646576008245",
"1229009290... | [
"nonn",
"easy",
"nice"
] | 662 | 0 | 3 | [
"A000027",
"A000217",
"A000290",
"A001090",
"A001108",
"A001109",
"A001353",
"A001542",
"A001653",
"A001850",
"A002315",
"A002965",
"A004189",
"A004191",
"A007655",
"A029547",
"A029548",
"A049660",
"A075843",
"A077412",
"A077421",
"A077423",
"A078987",
"A097309",
"A09... | [
"M4217",
"N1760"
] | N. J. A. Sloane | 2025-12-25T09:39:40 | oeisdata/seq/A001/A001109.seq | 9d7404db31061fe6a45cfa4cee31e42d |
A001110 | Square triangular numbers: numbers that are both triangular and square. | [
"0",
"1",
"36",
"1225",
"41616",
"1413721",
"48024900",
"1631432881",
"55420693056",
"1882672131025",
"63955431761796",
"2172602007770041",
"73804512832419600",
"2507180834294496361",
"85170343853180456676",
"2893284510173841030625",
"98286503002057414584576",
"33388478175597782548... | [
"nonn",
"easy",
"nice"
] | 427 | 0 | 3 | [
"A000217",
"A000290",
"A001014",
"A001108",
"A001109",
"A001110",
"A004146",
"A004191",
"A005214",
"A010052",
"A010054",
"A049682",
"A049683",
"A049684",
"A054493",
"A054686",
"A100047",
"A182334",
"A229131",
"A232847",
"A233267",
"A240129",
"A299921"
] | [
"M5259",
"N2291"
] | N. J. A. Sloane | 2025-11-03T13:12:55 | oeisdata/seq/A001/A001110.seq | 06e9c7804bf472fc060a7278dd278325 |
A001111 | Number of inequivalent Hadamard designs of order 4n. | [
"1",
"1",
"1",
"5",
"6",
"1106",
"208310",
"10374196953"
] | [
"nonn",
"hard",
"nice",
"more"
] | 23 | 1 | 4 | null | null | N. J. A. Sloane | 2023-09-19T05:13:27 | oeisdata/seq/A001/A001111.seq | 99fca3bfa9866b0c8dc313dc224f3a7e |
A001112 | A continued fraction. | [
"0",
"1",
"1",
"3",
"4",
"11",
"136",
"283",
"419",
"1121",
"1540",
"38081",
"39621",
"117323",
"156944",
"431211",
"5331476",
"11094163",
"16425639",
"43945441",
"60371080",
"1492851361",
"1553222441",
"4599296243",
"6152518684",
"16904333611",
"209004522016",
... | [
"nonn",
"frac",
"easy"
] | 30 | 0 | 4 | [
"A001112",
"A010211",
"A041298"
] | [
"M2370",
"N0939"
] | N. J. A. Sloane | 2022-09-08T08:44:28 | oeisdata/seq/A001/A001112.seq | 675124ebe690896e8782a358531b3c2f |
A001113 | Decimal expansion of e. | [
"2",
"7",
"1",
"8",
"2",
"8",
"1",
"8",
"2",
"8",
"4",
"5",
"9",
"0",
"4",
"5",
"2",
"3",
"5",
"3",
"6",
"0",
"2",
"8",
"7",
"4",
"7",
"1",
"3",
"5",
"2",
"6",
"6",
"2",
"4",
"9",
"7",
"7",
"5",
"7",
"2",
"4",
"7",
"0",
"9",
"... | [
"nonn",
"cons",
"nice",
"core",
"changed"
] | 390 | 1 | 1 | [
"A001113",
"A002034",
"A003417",
"A004593",
"A004594",
"A004595",
"A004596",
"A004597",
"A004598",
"A004599",
"A004600",
"A068985",
"A072334",
"A073229",
"A091933",
"A092426",
"A092511",
"A092513",
"A092553",
"A092555",
"A092560",
"A092577",
"A092578",
"A122214",
"A12... | [
"M1727",
"N0684"
] | N. J. A. Sloane | 2026-01-18T14:13:10 | oeisdata/seq/A001/A001113.seq | 9082652a0cc631af4e40331e82325ec2 |
A001114 | Increasing blocks of digits of e. | [
"2",
"7",
"18",
"28",
"182",
"845",
"904",
"5235",
"36028",
"74713",
"526624",
"977572",
"4709369",
"9959574",
"96696762",
"7724076630",
"35354759457",
"138217852516",
"642742746639",
"1932003059921",
"8174135966290",
"43572900334295",
"260595630738132",
"32862794349076... | [
"nonn",
"base"
] | 21 | 1 | 1 | null | [
"M1747",
"N0692"
] | N. J. A. Sloane | 2021-02-07T21:10:31 | oeisdata/seq/A001/A001114.seq | ccd0d623d08f2b38e61134a41fc62d28 |
A001115 | Maximal number of pairwise relatively prime polynomials of degree n over GF(2). | [
"1",
"2",
"3",
"4",
"6",
"9",
"14",
"23",
"38",
"64",
"113",
"200",
"358",
"653",
"1202",
"2223",
"4151",
"7781",
"14659",
"27721",
"52603",
"100084",
"190969",
"365134",
"699617",
"1342923",
"2582172",
"4972385",
"9588933",
"18515328",
"35794987",
"6927... | [
"nonn"
] | 22 | 0 | 2 | [
"A001037",
"A001115"
] | [
"M0575",
"N0209"
] | N. J. A. Sloane | 2021-12-19T10:58:34 | oeisdata/seq/A001/A001115.seq | 445453a7e41dc9d7e559aa74d360ee5a |
A001116 | Maximal kissing number of an n-dimensional lattice. | [
"0",
"2",
"6",
"12",
"24",
"40",
"72",
"126",
"240",
"272"
] | [
"nonn",
"nice",
"hard",
"more"
] | 71 | 0 | 2 | [
"A001116",
"A002336",
"A028923",
"A257479"
] | [
"M1585",
"N0617"
] | N. J. A. Sloane | 2025-06-02T16:49:53 | oeisdata/seq/A001/A001116.seq | 083b843c75223a7de7f398557ddbbc12 |
A001117 | a(n) = 3^n - 3*2^n + 3. | [
"1",
"0",
"0",
"6",
"36",
"150",
"540",
"1806",
"5796",
"18150",
"55980",
"171006",
"519156",
"1569750",
"4733820",
"14250606",
"42850116",
"128746950",
"386634060",
"1160688606",
"3483638676",
"10454061750",
"31368476700",
"94118013006",
"282379204836",
"8471879461... | [
"nonn",
"easy"
] | 101 | 0 | 4 | [
"A000919",
"A001117",
"A001118",
"A019538"
] | [
"M4219",
"N1763"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001117.seq | db2b93c12772897b7b49792eea1cc42c |
A001118 | Number of labeled ordered set partitions into 5 parts for n>=1, a(0)=1. | [
"1",
"0",
"0",
"0",
"0",
"120",
"1800",
"16800",
"126000",
"834120",
"5103000",
"29607600",
"165528000",
"901020120",
"4809004200",
"25292030400",
"131542866000",
"678330198120",
"3474971465400",
"17710714165200",
"89904730860000",
"454951508208120",
"2296538629446600",
... | [
"nonn",
"easy"
] | 82 | 0 | 6 | [
"A000919",
"A000920",
"A001117",
"A001118",
"A019538"
] | [
"M5377",
"N2334"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001118.seq | 2891c50cd410f84c13374180eb510809 |
A001119 | Number of skew-symmetric Hadamard matrices of order 4n. | [
"1",
"1",
"2",
"2",
"16",
"54"
] | [
"nonn",
"hard",
"more",
"nice"
] | 32 | 2 | 3 | [
"A001119",
"A007299"
] | null | N. J. A. Sloane | 2025-11-03T23:06:11 | oeisdata/seq/A001/A001119.seq | dc91ceca4585c606c19c7790aaf61393 |
A001120 | a(0) = a(1) = 1; for n > 1, a(n) = n*a(n-1) + (-1)^n. | [
"1",
"1",
"3",
"8",
"33",
"164",
"985",
"6894",
"55153",
"496376",
"4963761",
"54601370",
"655216441",
"8517813732",
"119249392249",
"1788740883734",
"28619854139745",
"486537520375664",
"8757675366761953",
"166395831968477106",
"3327916639369542121",
"69886249426760384540"... | [
"nonn",
"easy"
] | 55 | 0 | 3 | [
"A000142",
"A000166",
"A001120",
"A334715"
] | [
"M2760",
"N1110"
] | N. J. A. Sloane, Simon Plouffe | 2024-02-19T01:47:58 | oeisdata/seq/A001/A001120.seq | fd1f8a6e5d94008101f1e088a8cbf2aa |
A001121 | Number of doubly-regular tournaments of order 4n-1. | [
"1",
"1",
"2",
"2",
"37",
"722"
] | [
"nonn",
"hard",
"more",
"nice"
] | 15 | 2 | 3 | null | null | N. J. A. Sloane | 2017-05-02T21:48:41 | oeisdata/seq/A001/A001121.seq | b2951eefdc837a956145baf917872ad3 |
A001122 | Primes with primitive root 2. | [
"3",
"5",
"11",
"13",
"19",
"29",
"37",
"53",
"59",
"61",
"67",
"83",
"101",
"107",
"131",
"139",
"149",
"163",
"173",
"179",
"181",
"197",
"211",
"227",
"269",
"293",
"317",
"347",
"349",
"373",
"379",
"389",
"419",
"421",
"443",
"461",
"467",... | [
"nonn",
"easy",
"nice"
] | 301 | 1 | 1 | [
"A001122",
"A001123",
"A001913",
"A001917",
"A002326",
"A005596",
"A050229",
"A071642",
"A127209",
"A163782",
"A216838",
"A292270"
] | [
"M2473",
"N0981"
] | N. J. A. Sloane | 2025-12-07T15:17:14 | oeisdata/seq/A001/A001122.seq | 8b89c0e9cf8254a04c745d6f8e51c817 |
A001123 | Primes with 3 as smallest primitive root. | [
"7",
"17",
"31",
"43",
"79",
"89",
"113",
"127",
"137",
"199",
"223",
"233",
"257",
"281",
"283",
"331",
"353",
"401",
"449",
"463",
"487",
"521",
"569",
"571",
"593",
"607",
"617",
"631",
"641",
"691",
"739",
"751",
"809",
"811",
"823",
"857",
... | [
"nonn"
] | 59 | 1 | 1 | [
"A001122",
"A001123",
"A001124",
"A019334"
] | [
"M4356",
"N1825"
] | N. J. A. Sloane | 2023-02-13T11:16:43 | oeisdata/seq/A001/A001123.seq | 3dc9857df02260308f95de340b0a7adb |
A001124 | Primes with 5 as smallest primitive root. | [
"23",
"47",
"73",
"97",
"103",
"157",
"167",
"193",
"263",
"277",
"307",
"383",
"397",
"433",
"503",
"577",
"647",
"673",
"683",
"727",
"743",
"863",
"887",
"937",
"967",
"983",
"1033",
"1093",
"1103",
"1153",
"1163",
"1223",
"1367",
"1487",
"1543"... | [
"nonn"
] | 36 | 1 | 1 | [
"A001122",
"A001123",
"A001124",
"A001125"
] | [
"M5132",
"N2224"
] | N. J. A. Sloane | 2023-02-13T09:52:17 | oeisdata/seq/A001/A001124.seq | 124ec94c95dd0aa17628b26479f7fe98 |
A001125 | Primes with 6 as smallest primitive root. | [
"41",
"109",
"151",
"229",
"251",
"271",
"367",
"733",
"761",
"971",
"991",
"1069",
"1289",
"1303",
"1429",
"1471",
"1759",
"1789",
"1811",
"1879",
"2411",
"2441",
"2551",
"2749",
"2791",
"3061",
"3079",
"3109",
"3229",
"3251",
"3301",
"3319",
"3967",
... | [
"nonn"
] | 31 | 1 | 1 | [
"A001122",
"A001123",
"A001124",
"A001125"
] | [
"M5275",
"N2293"
] | N. J. A. Sloane | 2018-05-08T15:11:53 | oeisdata/seq/A001/A001125.seq | 444d93f6285ae08c2a7965abb53a3b5b |
A001126 | Primes with 7 as smallest primitive root. | [
"71",
"239",
"241",
"359",
"431",
"499",
"599",
"601",
"919",
"997",
"1051",
"1181",
"1249",
"1439",
"1609",
"1753",
"2039",
"2089",
"2111",
"2179",
"2251",
"2281",
"2341",
"2591",
"2593",
"2671",
"2711",
"2879",
"3119",
"3121",
"3169",
"3181",
"3457",... | [
"nonn"
] | 30 | 1 | 1 | null | [
"M5348",
"N2325"
] | N. J. A. Sloane | 2018-05-08T15:11:53 | oeisdata/seq/A001/A001126.seq | 0fe7e9498e089ac2c83cf737f3ad56b0 |
A001127 | Trajectory of 1 under map x->x + (x-with-digits-reversed). | [
"1",
"2",
"4",
"8",
"16",
"77",
"154",
"605",
"1111",
"2222",
"4444",
"8888",
"17776",
"85547",
"160105",
"661166",
"1322332",
"3654563",
"7309126",
"13528163",
"49710694",
"99312488",
"187733887",
"976071668",
"1842242347",
"9274664828",
"17559329557",
"9315172... | [
"nonn",
"base",
"easy",
"nice"
] | 35 | 0 | 2 | [
"A001127",
"A004086",
"A006960",
"A023108",
"A033648",
"A033649",
"A033650",
"A033651",
"A056964",
"A243238"
] | null | N. J. A. Sloane, Jun 05 2002 | 2023-10-27T18:03:38 | oeisdata/seq/A001/A001127.seq | 9976f572ec5c866423f93f1ed6a93984 |
A001128 | Reverse digits of previous term and multiply by previous term. | [
"2",
"4",
"16",
"976",
"662704",
"269896807264",
"124883600543123110859968",
"108643488775144622666209173128243503963147630528"
] | [
"nonn",
"base"
] | 19 | 1 | 1 | [
"A001128",
"A061205"
] | null | N. J. A. Sloane | 2025-11-15T16:20:37 | oeisdata/seq/A001/A001128.seq | bb113c5752c9939cd397a440eb12523b |
A001129 | Iccanobif numbers: reverse digits of two previous terms and add. | [
"0",
"1",
"1",
"2",
"3",
"5",
"8",
"13",
"39",
"124",
"514",
"836",
"1053",
"4139",
"12815",
"61135",
"104937",
"792517",
"1454698",
"9679838",
"17354310",
"9735140",
"1760750",
"986050",
"621360",
"113815",
"581437",
"1252496",
"7676706",
"13019288",
"943... | [
"nonn",
"base",
"easy",
"nice"
] | 59 | 0 | 4 | [
"A001129",
"A014258",
"A014259",
"A014260"
] | null | N. J. A. Sloane | 2025-07-05T05:22:31 | oeisdata/seq/A001/A001129.seq | aaf704fb4addc0e3e63ce591e931101c |
A001130 | Number of graphical basis partitions of 2n. | [
"1",
"1",
"3",
"4",
"6",
"11",
"16",
"23",
"36",
"52",
"71",
"103",
"141",
"197",
"272",
"366",
"482",
"657",
"863",
"1140",
"1489",
"1951",
"2511",
"3241",
"4155",
"5317",
"6782",
"8574",
"10786",
"13645",
"17111",
"21313",
"26631",
"33020",
"4100... | [
"nonn"
] | 29 | 1 | 3 | [
"A000041",
"A000569",
"A001130",
"A066447"
] | null | Pranav Kumar Tiwari (pktiwari(AT)eos.ncsu.edu) | 2015-09-17T19:58:29 | oeisdata/seq/A001/A001130.seq | 58ef206876d8ead29a1357a0b808e353 |
A001131 | Number of red-black rooted trees with n-1 internal nodes. | [
"0",
"1",
"2",
"2",
"3",
"8",
"14",
"20",
"35",
"64",
"122",
"260",
"586",
"1296",
"2708",
"5400",
"10468",
"19888",
"37580",
"71960",
"140612",
"279264",
"560544",
"1133760",
"2310316",
"4750368",
"9876264",
"20788880",
"44282696",
"95241664",
"206150208"... | [
"nonn"
] | 44 | 0 | 3 | [
"A001131",
"A001137",
"A014535",
"A037026"
] | null | Frank Ruskey | 2025-02-16T08:32:22 | oeisdata/seq/A001/A001131.seq | 6ceb3dc92e6b53647d9e59b668ba2c33 |
A001132 | Primes == +-1 (mod 8). | [
"7",
"17",
"23",
"31",
"41",
"47",
"71",
"73",
"79",
"89",
"97",
"103",
"113",
"127",
"137",
"151",
"167",
"191",
"193",
"199",
"223",
"233",
"239",
"241",
"257",
"263",
"271",
"281",
"311",
"313",
"337",
"353",
"359",
"367",
"383",
"401",
"409... | [
"nonn",
"nice",
"easy"
] | 80 | 1 | 1 | [
"A001132",
"A007519",
"A007522",
"A010051",
"A038873",
"A040028",
"A040098",
"A040159",
"A040992",
"A042966",
"A045315",
"A049542",
"A049595",
"A049596",
"A118905"
] | [
"M4354",
"N1824"
] | N. J. A. Sloane | 2022-05-22T09:40:10 | oeisdata/seq/A001/A001132.seq | 8b9cc0c868969e66143892c6ea979667 |
A001133 | Primes p such that the multiplicative order of 2 modulo p is (p-1)/3. | [
"43",
"109",
"157",
"229",
"277",
"283",
"307",
"499",
"643",
"691",
"733",
"739",
"811",
"997",
"1021",
"1051",
"1069",
"1093",
"1459",
"1579",
"1597",
"1627",
"1699",
"1723",
"1789",
"1933",
"2179",
"2203",
"2251",
"2341",
"2347",
"2749",
"2917",
"... | [
"nonn"
] | 30 | 1 | 1 | [
"A001133",
"A001134",
"A001135",
"A001136",
"A014752",
"A040028",
"A059914",
"A115586",
"A115591"
] | [
"M5283",
"N2299"
] | N. J. A. Sloane | 2022-09-08T08:44:28 | oeisdata/seq/A001/A001133.seq | 4fce0bdba4e7fa203d211e6a999cf34c |
A001134 | Primes p such that the multiplicative order of 2 modulo p is (p-1)/4. | [
"113",
"281",
"353",
"577",
"593",
"617",
"1033",
"1049",
"1097",
"1153",
"1193",
"1201",
"1481",
"1601",
"1889",
"2129",
"2273",
"2393",
"2473",
"3049",
"3089",
"3137",
"3217",
"3313",
"3529",
"3673",
"3833",
"4001",
"4217",
"4289",
"4457",
"4801",
"4... | [
"nonn"
] | 36 | 1 | 1 | [
"A001133",
"A001134",
"A001135",
"A001136",
"A115586",
"A115591"
] | [
"M5371",
"N2332"
] | N. J. A. Sloane | 2022-09-08T08:44:28 | oeisdata/seq/A001/A001134.seq | e6096423eeb0039a2fcb7dcbba5bd992 |
A001135 | Primes p such that the multiplicative order of 2 modulo p is (p-1)/5. | [
"251",
"571",
"971",
"1181",
"1811",
"2011",
"2381",
"2411",
"3221",
"3251",
"3301",
"3821",
"4211",
"4861",
"4931",
"5021",
"5381",
"5861",
"6221",
"6571",
"6581",
"8461",
"8501",
"9091",
"9461",
"10061",
"10211",
"10781",
"11251",
"11701",
"11941",
"12... | [
"nonn"
] | 29 | 1 | 1 | [
"A001133",
"A001134",
"A001135",
"A001136",
"A115586",
"A115591"
] | [
"M5424",
"N2356"
] | N. J. A. Sloane | 2023-12-12T12:18:21 | oeisdata/seq/A001/A001135.seq | f38005b90c76a4cf396d163f9a13de9d |
A001136 | Primes p such that the multiplicative order of 2 modulo p is (p-1)/6. | [
"31",
"223",
"433",
"439",
"457",
"727",
"919",
"1327",
"1399",
"1423",
"1471",
"1831",
"1999",
"2017",
"2287",
"2383",
"2671",
"2767",
"2791",
"2953",
"3271",
"3343",
"3457",
"3463",
"3607",
"3631",
"3823",
"3889",
"4129",
"4423",
"4519",
"4567",
"466... | [
"nonn"
] | 26 | 1 | 1 | [
"A001133",
"A001136"
] | [
"M5221",
"N2271"
] | N. J. A. Sloane | 2022-09-08T08:44:28 | oeisdata/seq/A001/A001136.seq | 6ebb3cb312c16ead810963b6552ead9a |
A001137 | Number of black-rooted red-black trees with n internal nodes. | [
"1",
"2",
"2",
"4",
"8",
"16",
"33",
"56",
"90",
"164",
"330",
"688",
"1440",
"3008",
"6291",
"13168",
"27604",
"57896",
"120730",
"248312",
"501464",
"995664",
"1954582",
"3821328",
"7495996",
"14848472",
"29815976",
"60741680",
"125363472",
"261452256",
... | [
"nonn"
] | 34 | 1 | 2 | [
"A001131",
"A001137"
] | null | Frank Ruskey | 2025-02-16T08:32:22 | oeisdata/seq/A001/A001137.seq | a766638cf1e6ceec320583fd2ecbd14a |
A001138 | Red rooted red-black trees with n internal nodes. | [
"1",
"0",
"1",
"4",
"6",
"4",
"2",
"8",
"32",
"96",
"256",
"608",
"1268",
"2392",
"4177",
"6720",
"9976",
"14064",
"19882",
"30952",
"59080",
"138096",
"355734",
"929040",
"2380268",
"5940408",
"14466720",
"34499984",
"80786736",
"186018208",
"421400951",
... | [
"nonn"
] | 19 | 1 | 4 | null | null | Frank Ruskey | 2025-02-16T08:32:22 | oeisdata/seq/A001/A001138.seq | 9f2ff23416405747fdaa9f4a1a2f8056 |
A001139 | Number of stable feedback shift registers with n stages. | [
"1",
"3",
"21",
"6615",
"64595475"
] | [
"nonn",
"more"
] | 19 | 2 | 2 | null | [
"M3088",
"N1252"
] | N. J. A. Sloane | 2022-02-02T00:07:06 | oeisdata/seq/A001/A001139.seq | 2181d8e856bed9abecbd51dbf90427df |
A001140 | Describe the previous term! (method A - initial term is 4). | [
"4",
"14",
"1114",
"3114",
"132114",
"1113122114",
"311311222114",
"13211321322114",
"1113122113121113222114",
"31131122211311123113322114",
"132113213221133112132123222114",
"11131221131211132221232112111312111213322114",
"31131122211311123113321112131221123113111231121123222114"
] | [
"nonn",
"base",
"easy",
"nice"
] | 58 | 1 | 1 | [
"A001140",
"A001141",
"A001143",
"A001145",
"A001151",
"A001154",
"A001155",
"A005150",
"A006715",
"A006751"
] | null | N. J. A. Sloane | 2024-07-29T08:43:43 | oeisdata/seq/A001/A001140.seq | da00734a29319362273fdfc2d0f1cbe9 |
A001141 | Describe the previous term! (method A - initial term is 5). | [
"5",
"15",
"1115",
"3115",
"132115",
"1113122115",
"311311222115",
"13211321322115",
"1113122113121113222115",
"31131122211311123113322115",
"132113213221133112132123222115"
] | [
"nonn",
"base",
"easy",
"nice"
] | 36 | 1 | 1 | [
"A001140",
"A001141",
"A001143",
"A001145",
"A001151",
"A001154",
"A001155",
"A005150",
"A006715",
"A006751"
] | null | N. J. A. Sloane | 2024-07-29T08:24:28 | oeisdata/seq/A001/A001141.seq | e47efd5e752751751f73ad17d2e0bd69 |
A001142 | a(n) = Product_{k=1..n} k^(2k - 1 - n). | [
"1",
"1",
"2",
"9",
"96",
"2500",
"162000",
"26471025",
"11014635520",
"11759522374656",
"32406091200000000",
"231627686043080250000",
"4311500661703860387840000",
"209706417310526095716965894400",
"26729809777664965932590782608648192"
] | [
"nonn",
"easy"
] | 175 | 0 | 3 | [
"A000178",
"A000225",
"A001142",
"A002109",
"A004788",
"A007318",
"A056077",
"A056606",
"A187059",
"A249151",
"A249343",
"A249345",
"A249346",
"A249347",
"A249421",
"A256113"
] | [
"M1953",
"N0773"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001142.seq | d3ce34e6adfc8c963b0bb18f3d810911 |
A001143 | Describe the previous term! (method A - initial term is 6). | [
"6",
"16",
"1116",
"3116",
"132116",
"1113122116",
"311311222116",
"13211321322116",
"1113122113121113222116",
"31131122211311123113322116",
"132113213221133112132123222116"
] | [
"nonn",
"base",
"easy",
"nice"
] | 31 | 1 | 1 | [
"A001140",
"A001141",
"A001143",
"A001145",
"A001151",
"A001154",
"A001155",
"A005150",
"A006715",
"A006751"
] | null | N. J. A. Sloane | 2023-08-30T05:20:56 | oeisdata/seq/A001/A001143.seq | fd56a0f40d82cdfe8b278b577b6ca8c1 |
A001144 | An exponential function on partitions (next term is 2^512). | [
"1",
"2",
"3",
"4",
"9",
"27",
"512",
"134217728"
] | [
"nonn"
] | 23 | 1 | 2 | [
"A000792",
"A001144",
"A014221"
] | [
"M0593",
"N0214"
] | N. J. A. Sloane | 2022-02-02T00:06:49 | oeisdata/seq/A001/A001144.seq | 720dd11f03263cc31d4e667bf462629a |
A001145 | Describe the previous term! (method A - initial term is 7). | [
"7",
"17",
"1117",
"3117",
"132117",
"1113122117",
"311311222117",
"13211321322117",
"1113122113121113222117",
"31131122211311123113322117",
"132113213221133112132123222117"
] | [
"nonn",
"base",
"easy",
"nice"
] | 24 | 1 | 1 | [
"A001140",
"A001141",
"A001143",
"A001145",
"A001151",
"A001154",
"A001155",
"A005150",
"A006715",
"A006751"
] | null | N. J. A. Sloane | 2019-04-14T10:26:30 | oeisdata/seq/A001/A001145.seq | bb11cfce4dcb3ffec5099dc50dfd866c |
A001146 | a(n) = 2^(2^n). | [
"2",
"4",
"16",
"256",
"65536",
"4294967296",
"18446744073709551616",
"340282366920938463463374607431768211456",
"115792089237316195423570985008687907853269984665640564039457584007913129639936"
] | [
"nonn",
"easy",
"nice"
] | 180 | 0 | 1 | [
"A000079",
"A000215",
"A001146",
"A003018",
"A007404",
"A026477",
"A051179",
"A062090",
"A062091",
"A112535",
"A155538",
"A165420",
"A173419",
"A215016",
"A247165",
"A247219"
] | [
"M1297",
"N0497"
] | N. J. A. Sloane | 2025-11-26T15:59:31 | oeisdata/seq/A001/A001146.seq | db6a57733009659db775de96ea9ebfb3 |
A001147 | Double factorial of odd numbers: a(n) = (2*n-1)!! = 1*3*5*...*(2*n-1). | [
"1",
"1",
"3",
"15",
"105",
"945",
"10395",
"135135",
"2027025",
"34459425",
"654729075",
"13749310575",
"316234143225",
"7905853580625",
"213458046676875",
"6190283353629375",
"191898783962510625",
"6332659870762850625",
"221643095476699771875",
"8200794532637891559375",
"31... | [
"nonn",
"easy",
"nice",
"core",
"changed"
] | 708 | 0 | 3 | [
"A000085",
"A000108",
"A000165",
"A000680",
"A000698",
"A001147",
"A001190",
"A001813",
"A001818",
"A006882",
"A009445",
"A028338",
"A029635",
"A033282",
"A039683",
"A051125",
"A053871",
"A055142",
"A060540",
"A076795",
"A079267",
"A082161",
"A086677",
"A086810",
"A08... | [
"M3002",
"N1217"
] | N. J. A. Sloane | 2026-01-16T13:23:50 | oeisdata/seq/A001/A001147.seq | fd2694875a059c2f29676791870793e4 |
A001148 | Final digit of 3^n. | [
"1",
"3",
"9",
"7",
"1",
"3",
"9",
"7",
"1",
"3",
"9",
"7",
"1",
"3",
"9",
"7",
"1",
"3",
"9",
"7",
"1",
"3",
"9",
"7",
"1",
"3",
"9",
"7",
"1",
"3",
"9",
"7",
"1",
"3",
"9",
"7",
"1",
"3",
"9",
"7",
"1",
"3",
"9",
"7",
"1",
"... | [
"nonn",
"cofr",
"easy"
] | 64 | 0 | 2 | [
"A001148",
"A001903",
"A159966",
"A388201"
] | null | N. J. A. Sloane | 2025-10-24T14:52:31 | oeisdata/seq/A001/A001148.seq | da6d6a9fc369b55e296ba839ce860a21 |
A001149 | A self-generating sequence: a(1)=1, a(2)=2, a(n+1) chosen so that a(n+1)-a(n-1) is the first number not obtainable as a(j)-a(i) for 1<=i<j<=n. | [
"1",
"2",
"3",
"5",
"8",
"13",
"17",
"26",
"34",
"45",
"54",
"67",
"81",
"97",
"115",
"132",
"153",
"171",
"198",
"228",
"256",
"288",
"323",
"357",
"400",
"439",
"488",
"530",
"581",
"627",
"681",
"732",
"790",
"843",
"908",
"963",
"1029",
"... | [
"nonn"
] | 38 | 1 | 2 | [
"A001149",
"A005282",
"A054540"
] | [
"M0689",
"N0254"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001149.seq | 0f49906df2e71b5cf5fa365da7b42515 |
A001150 | Number of n-input 2-output switching networks with GL(n,2) acting on the input and S(2) and C(2,2) acting on the output. | [
"3",
"13",
"146",
"40422",
"232328410830",
"2110021709419835241732893678",
"88336965390726143627393089434752334013039840509115817923869114"
] | [
"nonn"
] | 19 | 1 | 1 | null | [
"M2960",
"N1196"
] | N. J. A. Sloane | 2022-02-02T00:07:37 | oeisdata/seq/A001/A001150.seq | 48d2081c208f097a4a5a9d3b417c69c8 |
A001151 | Describe the previous term! (method A - initial term is 8). | [
"8",
"18",
"1118",
"3118",
"132118",
"1113122118",
"311311222118",
"13211321322118",
"1113122113121113222118",
"31131122211311123113322118",
"132113213221133112132123222118",
"11131221131211132221232112111312111213322118",
"31131122211311123113321112131221123113111231121123222118"
] | [
"nonn",
"base",
"easy",
"nice"
] | 31 | 1 | 1 | [
"A001140",
"A001141",
"A001143",
"A001145",
"A001151",
"A001154",
"A001155",
"A005150",
"A006715",
"A006751"
] | null | N. J. A. Sloane | 2024-09-15T22:09:35 | oeisdata/seq/A001/A001151.seq | 3c9e31a0bcb53a39f5b1a41422f137d2 |
A001152 | Number of n-input 3-output switching networks with GL(n,2) acting on the input and S(3) and C(2,3) acting on the output. | [
"4",
"36",
"3178",
"298908192",
"165073828103027338592",
"6487168790978377311010208151738379048817328948"
] | [
"nonn"
] | 19 | 1 | 1 | null | [
"M3668",
"N1494"
] | N. J. A. Sloane | 2022-02-02T00:07:50 | oeisdata/seq/A001/A001152.seq | 96140d55e27e3bd2bbea0104dd6d10e6 |
A001153 | Degrees of primitive irreducible trinomials: n such that 2^n - 1 is a Mersenne prime and x^n + x^k + 1 is a primitive irreducible polynomial over GF(2) for some k with 0 < k < n. | [
"2",
"3",
"5",
"7",
"17",
"31",
"89",
"127",
"521",
"607",
"1279",
"2281",
"3217",
"4423",
"9689",
"19937",
"23209",
"44497",
"110503",
"132049",
"756839",
"859433",
"3021377",
"6972593",
"24036583",
"25964951",
"30402457",
"32582657",
"42643801",
"43112609"... | [
"nonn",
"nice",
"hard",
"more"
] | 64 | 1 | 1 | [
"A000043",
"A001153",
"A002475",
"A057486",
"A073571",
"A073639",
"A073726",
"A074743"
] | [
"M0678",
"N0250"
] | N. J. A. Sloane | 2018-08-06T05:22:50 | oeisdata/seq/A001/A001153.seq | b257eb552cd04c95d8a0b3f589efda19 |
A001154 | Describe the previous term! (method A - initial term is 9). | [
"9",
"19",
"1119",
"3119",
"132119",
"1113122119",
"311311222119",
"13211321322119",
"1113122113121113222119",
"31131122211311123113322119",
"132113213221133112132123222119"
] | [
"nonn",
"base",
"easy",
"nice"
] | 26 | 1 | 1 | [
"A001140",
"A001141",
"A001143",
"A001145",
"A001151",
"A001154",
"A001155",
"A005150",
"A006715",
"A006751"
] | null | N. J. A. Sloane | 2019-04-14T10:27:11 | oeisdata/seq/A001/A001154.seq | b9fcf29a7bc79b45ba16e195d9cb7202 |
A001155 | Describe the previous term! (method A - initial term is 0). | [
"0",
"10",
"1110",
"3110",
"132110",
"1113122110",
"311311222110",
"13211321322110",
"1113122113121113222110",
"31131122211311123113322110",
"132113213221133112132123222110",
"11131221131211132221232112111312111213322110",
"31131122211311123113321112131221123113111231121123222110"
] | [
"nonn",
"base",
"easy",
"nice"
] | 44 | 1 | 2 | [
"A001140",
"A001141",
"A001143",
"A001145",
"A001151",
"A001154",
"A001155",
"A005150",
"A006715",
"A006751",
"A036058"
] | null | N. J. A. Sloane | 2023-03-02T15:55:23 | oeisdata/seq/A001/A001155.seq | 3738e923077425c8ba03a0865d35b02a |
A001156 | Number of partitions of n into squares. | [
"1",
"1",
"1",
"1",
"2",
"2",
"2",
"2",
"3",
"4",
"4",
"4",
"5",
"6",
"6",
"6",
"8",
"9",
"10",
"10",
"12",
"13",
"14",
"14",
"16",
"19",
"20",
"21",
"23",
"26",
"27",
"28",
"31",
"34",
"37",
"38",
"43",
"46",
"49",
"50",
"55",
"60",
... | [
"nonn",
"easy",
"changed"
] | 129 | 0 | 5 | [
"A000041",
"A000161",
"A000290",
"A001156",
"A001462",
"A003108",
"A003114",
"A006141",
"A010052",
"A011757",
"A033461",
"A037444",
"A039900",
"A046042",
"A047993",
"A052335",
"A062457",
"A064174",
"A078134",
"A078135",
"A109298",
"A117144",
"A131799",
"A218494",
"A24... | [
"M0221",
"N0079"
] | N. J. A. Sloane | 2026-01-14T16:22:19 | oeisdata/seq/A001/A001156.seq | c77a3992465a4f983b4b61db25b5a986 |
A001157 | a(n) = sigma_2(n): sum of squares of divisors of n. | [
"1",
"5",
"10",
"21",
"26",
"50",
"50",
"85",
"91",
"130",
"122",
"210",
"170",
"250",
"260",
"341",
"290",
"455",
"362",
"546",
"500",
"610",
"530",
"850",
"651",
"850",
"820",
"1050",
"842",
"1300",
"962",
"1365",
"1220",
"1450",
"1300",
"1911"... | [
"nonn",
"core",
"nice",
"easy",
"mult"
] | 159 | 1 | 2 | [
"A000005",
"A000203",
"A001157",
"A001158",
"A001159",
"A048250",
"A053807",
"A064602",
"A082063",
"A127093",
"A134841",
"A179931",
"A192794",
"A192795",
"A242639",
"A333972"
] | [
"M3799",
"N1551"
] | N. J. A. Sloane, R. K. Guy | 2025-12-01T10:36:34 | oeisdata/seq/A001/A001157.seq | 6f5fecc60dd02ca9155ead1f411ea7a6 |
A001158 | sigma_3(n): sum of cubes of divisors of n. | [
"1",
"9",
"28",
"73",
"126",
"252",
"344",
"585",
"757",
"1134",
"1332",
"2044",
"2198",
"3096",
"3528",
"4681",
"4914",
"6813",
"6860",
"9198",
"9632",
"11988",
"12168",
"16380",
"15751",
"19782",
"20440",
"25112",
"24390",
"31752",
"29792",
"37449",
... | [
"nonn",
"easy",
"nice",
"mult"
] | 140 | 1 | 2 | [
"A000005",
"A000203",
"A001157",
"A001158",
"A004009",
"A027748",
"A051731",
"A064603",
"A124010",
"A127093"
] | [
"M4605",
"N1964"
] | N. J. A. Sloane, R. K. Guy | 2025-09-22T16:00:14 | oeisdata/seq/A001/A001158.seq | 0832075a02342e65b809d597abb7527c |
A001159 | sigma_4(n): sum of 4th powers of divisors of n. | [
"1",
"17",
"82",
"273",
"626",
"1394",
"2402",
"4369",
"6643",
"10642",
"14642",
"22386",
"28562",
"40834",
"51332",
"69905",
"83522",
"112931",
"130322",
"170898",
"196964",
"248914",
"279842",
"358258",
"391251",
"485554",
"538084",
"655746",
"707282",
"87... | [
"nonn",
"easy",
"mult"
] | 76 | 1 | 2 | [
"A000005",
"A000203",
"A001157",
"A001158",
"A001159",
"A064604"
] | [
"M5041",
"N2177"
] | N. J. A. Sloane | 2025-11-13T04:08:26 | oeisdata/seq/A001/A001159.seq | 01d7acb2ba84d58d6244c8bcf02cd1c8 |
A001160 | sigma_5(n), the sum of the 5th powers of the divisors of n. | [
"1",
"33",
"244",
"1057",
"3126",
"8052",
"16808",
"33825",
"59293",
"103158",
"161052",
"257908",
"371294",
"554664",
"762744",
"1082401",
"1419858",
"1956669",
"2476100",
"3304182",
"4101152",
"5314716",
"6436344",
"8253300",
"9768751",
"12252702",
"14408200",
... | [
"nonn",
"easy",
"mult"
] | 70 | 1 | 2 | [
"A000005",
"A000203",
"A000584",
"A001157",
"A001158",
"A001159",
"A001160",
"A013973",
"A178448",
"A248076"
] | [
"M5240",
"N2279"
] | N. J. A. Sloane | 2025-11-13T04:06:32 | oeisdata/seq/A001/A001160.seq | d53a494bf8b70ffe149ff224d91efe7e |
A001161 | Numbers containing an even number of letters. | [
"0",
"4",
"5",
"9",
"11",
"12",
"13",
"14",
"18",
"19",
"20",
"24",
"25",
"29",
"30",
"34",
"35",
"39",
"41",
"42",
"43",
"46",
"47",
"48",
"51",
"52",
"53",
"56",
"57",
"58",
"61",
"62",
"63",
"66",
"67",
"68",
"71",
"72",
"73",
"76",
... | [
"nonn",
"word"
] | 8 | 1 | 2 | [
"A001161",
"A001162",
"A005589"
] | null | William P. Everts [ bille(AT)regenisys.com ] | 2013-09-04T05:12:57 | oeisdata/seq/A001/A001161.seq | 154a2d2302dabb3c18102373cc4df131 |
A001162 | Numbers containing an odd number of letters. | [
"1",
"2",
"3",
"6",
"7",
"8",
"10",
"15",
"16",
"17",
"21",
"22",
"23",
"26",
"27",
"28",
"31",
"32",
"33",
"36",
"37",
"38",
"40",
"44",
"45",
"49",
"50",
"54",
"55",
"59",
"60",
"64",
"65",
"69",
"70",
"74",
"75",
"79",
"81",
"82",
"8... | [
"nonn",
"word"
] | 8 | 1 | 2 | [
"A001161",
"A001162",
"A005589"
] | null | William P. Everts [ bille(AT)regenisys.com ] | 2013-09-04T05:12:50 | oeisdata/seq/A001/A001162.seq | d3362effd61ee08052579b00c522b940 |
A001163 | Stirling's formula: numerators of asymptotic series for Gamma function. | [
"1",
"1",
"1",
"-139",
"-571",
"163879",
"5246819",
"-534703531",
"-4483131259",
"432261921612371",
"6232523202521089",
"-25834629665134204969",
"-1579029138854919086429",
"746590869962651602203151",
"1511513601028097903631961",
"-8849272268392873147705987190261",
"-14280171249060753... | [
"sign",
"frac",
"nice"
] | 107 | 0 | 4 | [
"A001163",
"A001164",
"A097303",
"A143475",
"A143476",
"A317747",
"A317796",
"A318713",
"A318714"
] | [
"M5400",
"N2347"
] | N. J. A. Sloane | 2025-11-10T21:50:37 | oeisdata/seq/A001/A001163.seq | 64945fbf06e2195dfb542a53f7c799dc |
A001164 | Stirling's formula: denominators of asymptotic series for Gamma function. | [
"1",
"12",
"288",
"51840",
"2488320",
"209018880",
"75246796800",
"902961561600",
"86684309913600",
"514904800886784000",
"86504006548979712000",
"13494625021640835072000",
"9716130015581401251840000",
"116593560186976815022080000",
"2798245444487443560529920000",
"29969208710460520533... | [
"nonn",
"frac",
"nice"
] | 80 | 0 | 2 | [
"A001163",
"A001164",
"A143475",
"A143476",
"A317747",
"A317796"
] | [
"M4878",
"N2091"
] | N. J. A. Sloane | 2025-11-10T21:50:37 | oeisdata/seq/A001/A001164.seq | df91f67f91bd854a1506ad9db82a2f7d |
A001165 | Position of first even digit after decimal point in sqrt(n). | [
"1",
"1",
"3",
"1",
"1",
"1",
"1",
"1",
"1",
"2",
"3",
"1",
"1",
"2",
"1",
"1",
"2",
"1",
"3",
"1",
"2",
"1",
"4",
"1",
"1",
"1",
"3",
"1",
"2",
"1",
"2",
"1",
"2",
"1",
"3",
"1",
"1",
"2",
"1",
"2",
"1",
"1",
"4",
"1",
"2",
"... | [
"nonn",
"base"
] | 17 | 1 | 3 | null | null | Howard Givner | 2019-04-17T10:07:54 | oeisdata/seq/A001/A001165.seq | f7635be37b562c2ccebca467f316d6d7 |
A001166 | Smallest natural number requiring n letters in English. | [
"1",
"4",
"3",
"11",
"15",
"13",
"17",
"24",
"23",
"73",
"3000",
"11000",
"15000",
"101",
"104",
"103",
"111",
"115",
"113",
"117",
"124",
"123",
"173",
"323",
"373",
"1104",
"1103",
"1111",
"1115",
"1113",
"1117",
"1124",
"1123",
"1173",
"1323",
... | [
"word",
"nonn"
] | 39 | 3 | 2 | [
"A000916",
"A001166",
"A014388",
"A045494",
"A045495",
"A080777"
] | [
"M3215",
"N1301"
] | N. J. A. Sloane | 2025-10-12T20:59:22 | oeisdata/seq/A001/A001166.seq | 4afec423692acb2459d82cbccc6d1139 |
A001167 | Smallest natural number requiring n words in English (as spoken in England). | [
"1",
"21",
"21000",
"101",
"121",
"1101",
"1121",
"21121",
"101101",
"101121",
"121121",
"1101121",
"1121121",
"21121121",
"101101121",
"101121121",
"121121121",
"1101121121",
"1121121121",
"21121121121",
"101101121121",
"101121121121",
"121121121121",
"1101121121121",
... | [
"nonn",
"word"
] | 29 | 1 | 2 | null | [
"M5122",
"N2218"
] | N. J. A. Sloane | 2023-01-13T21:13:02 | oeisdata/seq/A001/A001167.seq | d386896ee80d2f1695321ceac60e88be |
A001168 | Number of fixed polyominoes with n cells. | [
"1",
"1",
"2",
"6",
"19",
"63",
"216",
"760",
"2725",
"9910",
"36446",
"135268",
"505861",
"1903890",
"7204874",
"27394666",
"104592937",
"400795844",
"1540820542",
"5940738676",
"22964779660",
"88983512783",
"345532572678",
"1344372335524",
"5239988770268",
"204578... | [
"nonn",
"nice"
] | 188 | 0 | 3 | [
"A000105",
"A000988",
"A001168",
"A006746",
"A006747",
"A006748",
"A006749",
"A006762",
"A056877",
"A056878",
"A142886",
"A144553",
"A210986",
"A210987",
"A308359",
"A366767",
"A391197"
] | [
"M1639",
"N0641"
] | N. J. A. Sloane | 2025-12-08T11:03:34 | oeisdata/seq/A001/A001168.seq | ed0a09ed39de816dc3c3835e990968e3 |
A001169 | Number of board-pile polyominoes with n cells. | [
"1",
"2",
"6",
"19",
"61",
"196",
"629",
"2017",
"6466",
"20727",
"66441",
"212980",
"682721",
"2188509",
"7015418",
"22488411",
"72088165",
"231083620",
"740754589",
"2374540265",
"7611753682",
"24400004911",
"78215909841",
"250726529556",
"803721298537",
"25763844... | [
"nonn",
"nice",
"easy"
] | 103 | 1 | 2 | [
"A001169",
"A049219",
"A049220",
"A049221",
"A049222",
"A246773",
"A273895"
] | [
"M1636",
"N0639"
] | N. J. A. Sloane | 2025-11-26T15:59:31 | oeisdata/seq/A001/A001169.seq | ab2a980232efd077d5cd374eceade775 |
A001170 | Number of board-pair-pile polyominoes with n cells. | [
"1",
"2",
"6",
"19",
"63",
"216",
"760",
"2723",
"9880",
"36168",
"133237",
"492993",
"1829670",
"6804267",
"25336611",
"94416842",
"351989967",
"1312471879",
"4894023222",
"18248301701",
"68036380665",
"253638655582",
"945464013411",
"3523978989671",
"13133649924269"... | [
"nonn"
] | 26 | 1 | 2 | null | [
"M1638",
"N0640"
] | N. J. A. Sloane | 2022-02-02T00:07:22 | oeisdata/seq/A001/A001170.seq | 25902b58131762f06d76b702b8be6ea7 |
A001171 | From least significant term in expansion of E( tr (X'*X)^n ), X rectangular and Gaussian. Also number of types of sequential n-swap moves for traveling salesman problem. | [
"1",
"1",
"4",
"20",
"148",
"1348",
"15104",
"198144",
"2998656",
"51290496",
"979732224",
"20661458688",
"476936766720",
"11959743432960",
"323764901314560",
"9410647116349440",
"292316310979706880",
"9663569062008422400",
"338760229843058688000"
] | [
"nonn",
"nice"
] | 48 | 1 | 3 | [
"A001171",
"A061714"
] | [
"M3570",
"N1447"
] | Colin Mallows | 2025-11-05T15:21:39 | oeisdata/seq/A001/A001171.seq | 0174b9c84f6fe64f22c0335cc49276fd |
A001172 | Smallest even number that is an unordered sum of two odd primes in exactly n ways. | [
"0",
"6",
"10",
"22",
"34",
"48",
"60",
"78",
"84",
"90",
"114",
"144",
"120",
"168",
"180",
"234",
"246",
"288",
"240",
"210",
"324",
"300",
"360",
"474",
"330",
"528",
"576",
"390",
"462",
"480",
"420",
"570",
"510",
"672",
"792",
"756",
"876... | [
"nonn",
"nice",
"look",
"easy"
] | 38 | 0 | 2 | [
"A000954",
"A000974",
"A001172",
"A002375",
"A005843",
"A023036",
"A258713"
] | [
"M4085",
"N1694"
] | N. J. A. Sloane, Eric Wolman, Dec 17 1969 | 2021-12-11T11:05:25 | oeisdata/seq/A001/A001172.seq | 17145352788147ade0fde1cfb37e75ad |
A001173 | Half the number of binary relations on n unlabeled points. | [
"1",
"5",
"52",
"1522",
"145984",
"48464496",
"56141454464",
"229148550030864",
"3333310786076963968",
"174695272746749919580928",
"33301710992539090379269318144",
"23278728241293494533015563325552128",
"60084295633556503802059558812644803074048",
"57602507788023707877694673087161838615157... | [
"nonn",
"nice"
] | 51 | 1 | 2 | [
"A000595",
"A001173",
"A001174"
] | [
"M4010",
"N1662"
] | N. J. A. Sloane | 2024-07-05T16:12:42 | oeisdata/seq/A001/A001173.seq | 459d71ebe377d9e3905f4d6b97e4860e |
A001174 | Number of oriented graphs (i.e., digraphs with no bidirected edges) on n unlabeled nodes. Also number of complete digraphs on n unlabeled nodes. Number of antisymmetric relations (i.e., oriented graphs with loops) on n unlabeled nodes is A083670. | [
"1",
"2",
"7",
"42",
"582",
"21480",
"2142288",
"575016219",
"415939243032",
"816007449011040",
"4374406209970747314",
"64539836938720749739356",
"2637796735571225009053373136",
"300365896158980530053498490893399"
] | [
"nonn",
"nice",
"easy"
] | 56 | 1 | 2 | [
"A000595",
"A001173",
"A001174",
"A047656",
"A054941",
"A086345",
"A281446"
] | [
"M1809",
"N0715"
] | N. J. A. Sloane | 2025-11-05T15:21:39 | oeisdata/seq/A001/A001174.seq | ffd8348e8061da1916bfb12cc9a5267c |
A001175 | Pisano periods (or Pisano numbers): period of Fibonacci numbers mod n. | [
"1",
"3",
"8",
"6",
"20",
"24",
"16",
"12",
"24",
"60",
"10",
"24",
"28",
"48",
"40",
"24",
"36",
"24",
"18",
"60",
"16",
"30",
"48",
"24",
"100",
"84",
"72",
"48",
"14",
"120",
"30",
"48",
"40",
"36",
"80",
"24",
"76",
"18",
"56",
"60",
... | [
"nonn",
"nice"
] | 257 | 1 | 2 | [
"A001175",
"A001178",
"A001179",
"A003893",
"A060305",
"A066853",
"A222413",
"A235702",
"A296240"
] | [
"M2710",
"N1087"
] | N. J. A. Sloane | 2025-11-26T15:59:31 | oeisdata/seq/A001/A001175.seq | aa3b62ceef4a663a4f07d0bc1e9968ab |
A001176 | Number of zeros in fundamental period of Fibonacci numbers mod n. | [
"1",
"1",
"2",
"1",
"4",
"2",
"2",
"2",
"2",
"4",
"1",
"2",
"4",
"2",
"2",
"2",
"4",
"2",
"1",
"2",
"2",
"1",
"2",
"2",
"4",
"4",
"2",
"2",
"1",
"2",
"1",
"2",
"2",
"4",
"2",
"2",
"4",
"1",
"2",
"2",
"2",
"2",
"2",
"1",
"2",
"... | [
"nonn",
"easy"
] | 70 | 1 | 3 | [
"A001175",
"A001176",
"A001177",
"A053027",
"A053028",
"A053029",
"A053030",
"A053031",
"A053032",
"A235715"
] | [
"M0165",
"N0064"
] | N. J. A. Sloane | 2022-02-22T23:08:47 | oeisdata/seq/A001/A001176.seq | 00a29052b31518a3c8759091b4c58883 |
A001177 | Fibonacci entry points: a(n) = least k >= 1 such that n divides Fibonacci number F_k (=A000045(k)). | [
"1",
"3",
"4",
"6",
"5",
"12",
"8",
"6",
"12",
"15",
"10",
"12",
"7",
"24",
"20",
"12",
"9",
"12",
"18",
"30",
"8",
"30",
"24",
"12",
"25",
"21",
"36",
"24",
"14",
"60",
"30",
"24",
"20",
"9",
"40",
"12",
"19",
"18",
"28",
"30",
"20",
... | [
"nonn"
] | 219 | 1 | 2 | [
"A000045",
"A000057",
"A000217",
"A001175",
"A001176",
"A001177",
"A001602",
"A037943",
"A046737",
"A047930",
"A060383",
"A106535",
"A120255",
"A120256",
"A131401",
"A132632",
"A132633",
"A175026",
"A213648",
"A214028",
"A214031",
"A214528",
"A214781",
"A214783",
"A21... | [
"M2314",
"N0914"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001177.seq | 421dc3b8202b804d7fca5f9dde7a2318 |
A001178 | Fibonacci frequency of n. | [
"0",
"4",
"3",
"2",
"3",
"1",
"2",
"2",
"1",
"2",
"3",
"1",
"3",
"2",
"3",
"1",
"2",
"1",
"2",
"2",
"2",
"2",
"2",
"0",
"3",
"3",
"2",
"2",
"3",
"1",
"2",
"2",
"3",
"2",
"2",
"1",
"3",
"2",
"3",
"2",
"3",
"2",
"3",
"2",
"1",
"... | [
"nonn"
] | 37 | 1 | 2 | [
"A001175",
"A001178",
"A235702"
] | [
"M3207",
"N1298"
] | N. J. A. Sloane | 2022-02-28T14:59:57 | oeisdata/seq/A001/A001178.seq | 58a177053d6ab5defb090136661088c1 |
A001179 | Leonardo logarithm of n. | [
"0",
"1",
"1",
"1",
"2",
"1",
"1",
"1",
"1",
"2",
"2",
"1",
"1",
"1",
"2",
"1",
"1",
"1",
"1",
"2",
"1",
"2",
"1",
"1",
"3",
"1",
"1",
"1",
"1",
"2",
"2",
"1",
"2",
"1",
"2",
"1",
"1",
"1",
"1",
"2",
"2",
"1",
"2",
"2",
"2",
"... | [
"nonn",
"nice"
] | 32 | 1 | 5 | [
"A001175",
"A001179",
"A235249"
] | [
"M0052",
"N0017"
] | N. J. A. Sloane | 2024-10-22T09:45:24 | oeisdata/seq/A001/A001179.seq | 2ea3df3b27f07c1cb0e3dd36b69350f1 |
A001180 | Erroneous version of A002572. | [
"1",
"1",
"2",
"3",
"3",
"5",
"9",
"16",
"28",
"50",
"89",
"159",
"285",
"510",
"914",
"1639",
"2938",
"5269",
"9451",
"16952"
] | [
"dead"
] | 7 | 1 | 3 | null | [
"M0442",
"N0165"
] | null | 2010-06-01T03:00:00 | oeisdata/seq/A001/A001180.seq | eab9ec59fcd911ee0a304825a12f451a |
A001181 | Number of Baxter permutations of length n (also called Baxter numbers). | [
"1",
"1",
"2",
"6",
"22",
"92",
"422",
"2074",
"10754",
"58202",
"326240",
"1882960",
"11140560",
"67329992",
"414499438",
"2593341586",
"16458756586",
"105791986682",
"687782586844",
"4517543071924",
"29949238543316",
"200234184620736",
"1349097425104912",
"91542766186... | [
"nonn",
"nice",
"easy"
] | 342 | 0 | 3 | [
"A001181",
"A001183",
"A001185",
"A006002",
"A007318",
"A046996",
"A056939",
"A359363"
] | [
"M1661",
"N0652"
] | N. J. A. Sloane, Simon Plouffe | 2025-12-06T10:43:48 | oeisdata/seq/A001/A001181.seq | 33425cb88582a0e8c09ff082735d21ac |
A001182 | Number of cells of square lattice of edge 1/n inside quadrant of unit circle centered at 0. | [
"0",
"1",
"4",
"8",
"15",
"22",
"30",
"41",
"54",
"69",
"83",
"98",
"119",
"139",
"162",
"183",
"208",
"234",
"263",
"294",
"322",
"357",
"390",
"424",
"465",
"504",
"545",
"585",
"628",
"675",
"719",
"770",
"819",
"872",
"928",
"977",
"1036",
... | [
"nonn"
] | 26 | 1 | 3 | [
"A001182",
"A242118",
"A261849",
"A281795"
] | null | Tihamer von Ghyczy (ghyczy(AT)esinet.net) | 2024-07-18T21:02:35 | oeisdata/seq/A001/A001182.seq | efca174cb82d33de8da176d55271dca1 |
A001183 | Number of nontrivial Baxter permutations of length 2n-1. | [
"0",
"2",
"2",
"18",
"66",
"374",
"1694",
"9822",
"51698"
] | [
"nonn",
"more"
] | 25 | 1 | 2 | [
"A001181",
"A001183",
"A001185",
"A046996"
] | [
"M0390",
"N0148"
] | N. J. A. Sloane | 2024-10-23T16:12:35 | oeisdata/seq/A001/A001183.seq | a4f139346535682c815c50fd0b3a055c |
A001184 | Number of simple Hamiltonian paths connecting opposite corners of a 2n+1 X 2n+1 grid. | [
"1",
"2",
"104",
"111712",
"2688307514",
"1445778936756068",
"17337631013706758184626",
"4628650743368437273677525554148",
"27478778338807945303765092195103685118924"
] | [
"nonn",
"more",
"walk"
] | 19 | 0 | 2 | [
"A001184",
"A121788",
"A333580"
] | null | Don Knuth, Dec 07 1995 | 2022-01-30T12:31:25 | oeisdata/seq/A001/A001184.seq | 879b24e26da9201414bf9035badb1f22 |
A001185 | Number of nontrivial Baxter permutations of length 2n-1. | [
"0",
"1",
"1",
"7",
"21",
"112",
"456",
"2603",
"13203"
] | [
"nonn",
"nice",
"more"
] | 22 | 1 | 4 | [
"A001181",
"A001183",
"A001185"
] | [
"M4372",
"N1837"
] | N. J. A. Sloane | 2024-10-23T16:13:03 | oeisdata/seq/A001/A001185.seq | 6eea504befd57322aa197308e2c34d8b |
A001186 | Number of cubic Hamiltonian graphs with 2n nodes. | [
"1",
"2",
"5",
"17",
"80",
"474",
"3841",
"39635",
"495991",
"7170657",
"116171803",
"2070451150",
"40130198979",
"839266928707",
"18826133329753"
] | [
"nonn",
"hard",
"nice",
"more"
] | 54 | 2 | 2 | null | null | Martin Harborth (Martin.Harborth(AT)vt.siemens.de) | 2025-11-05T15:21:39 | oeisdata/seq/A001/A001186.seq | e36cf1f79fd9635963ad221fae786f70 |
A001187 | Number of connected labeled graphs with n nodes. | [
"1",
"1",
"1",
"4",
"38",
"728",
"26704",
"1866256",
"251548592",
"66296291072",
"34496488594816",
"35641657548953344",
"73354596206766622208",
"301272202649664088951808",
"2471648811030443735290891264",
"40527680937730480234609755344896",
"1328578958335783201008338986845427712"
] | [
"nonn",
"nice",
"easy"
] | 181 | 0 | 4 | [
"A001187",
"A006125",
"A053549",
"A062734"
] | [
"M3671",
"N1496"
] | N. J. A. Sloane | 2025-11-05T15:21:39 | oeisdata/seq/A001/A001187.seq | bf35034c0947deb7daeeae2db6e91c44 |
A001188 | Number of even graphs with n edges. | [
"1",
"2",
"8",
"60",
"672",
"9953",
"184557",
"4142631",
"109813842",
"3373122370",
"118280690398",
"4678086540493",
"206625802351035",
"10107719377251109",
"543762148079927802",
"31975474310851749920",
"2044501883873268414092",
"141485408653554069693421"
] | [
"nonn"
] | 24 | 1 | 2 | null | [
"M1892",
"N0746"
] | N. J. A. Sloane | 2015-06-15T18:31:13 | oeisdata/seq/A001/A001188.seq | 9ff8d726b1af800d10b49e9e5d923247 |
A001189 | Number of degree-n permutations of order exactly 2. | [
"0",
"1",
"3",
"9",
"25",
"75",
"231",
"763",
"2619",
"9495",
"35695",
"140151",
"568503",
"2390479",
"10349535",
"46206735",
"211799311",
"997313823",
"4809701439",
"23758664095",
"119952692895",
"618884638911",
"3257843882623",
"17492190577599",
"95680443760575",
... | [
"nonn",
"nice",
"easy"
] | 61 | 1 | 3 | [
"A001189",
"A001470",
"A001473",
"A052501",
"A053496",
"A053504",
"A057731",
"A061121",
"A061128",
"A080510",
"A143911",
"A182222"
] | [
"M2801",
"N1127"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001189.seq | 1b1e34382ea0bf3392227c0b6fdd28d3 |
A001190 | Wedderburn-Etherington numbers: unlabeled binary rooted trees (every node has outdegree 0 or 2) with n endpoints (and 2n-1 nodes in all). | [
"0",
"1",
"1",
"1",
"2",
"3",
"6",
"11",
"23",
"46",
"98",
"207",
"451",
"983",
"2179",
"4850",
"10905",
"24631",
"56011",
"127912",
"293547",
"676157",
"1563372",
"3626149",
"8436379",
"19680277",
"46026618",
"107890609",
"253450711",
"596572387",
"140681... | [
"easy",
"core",
"nonn",
"nice",
"eigen",
"changed"
] | 324 | 0 | 5 | [
"A000108",
"A001190",
"A001699",
"A002658",
"A003214",
"A006894",
"A006961",
"A086317",
"A086318",
"A088325",
"A240943",
"A292085",
"A292553",
"A292554",
"A292555",
"A292556",
"A299038",
"A319539",
"A319541"
] | [
"M0790",
"N0298"
] | N. J. A. Sloane | 2026-01-17T07:11:40 | oeisdata/seq/A001/A001190.seq | a410237a9098e1487dcec016e01ea55c |
A001191 | Digits of positive squares. | [
"1",
"4",
"9",
"1",
"6",
"2",
"5",
"3",
"6",
"4",
"9",
"6",
"4",
"8",
"1",
"1",
"0",
"0",
"1",
"2",
"1",
"1",
"4",
"4",
"1",
"6",
"9",
"1",
"9",
"6",
"2",
"2",
"5",
"2",
"5",
"6",
"2",
"8",
"9",
"3",
"2",
"4",
"3",
"6",
"1",
"... | [
"nonn",
"base",
"easy"
] | 48 | 1 | 2 | null | null | Charlie Peck (peck(AT)Alice.Wonderland.Caltech.EDU) | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001191.seq | 047df18a054a4d9f1464c04843c72ae8 |
A001192 | Number of full sets of size n. | [
"1",
"1",
"1",
"2",
"9",
"88",
"1802",
"75598",
"6421599",
"1097780312",
"376516036188",
"258683018091900",
"355735062429124915",
"978786413996934006272",
"5387230452634185460127166",
"59308424712939278997978128490",
"1305926814154452720947815884466579"
] | [
"nonn",
"nice"
] | 64 | 0 | 4 | [
"A000295",
"A001192",
"A004111",
"A115728",
"A182161",
"A279861",
"A279863"
] | [
"M1951",
"N0772"
] | N. J. A. Sloane | 2025-11-05T15:35:23 | oeisdata/seq/A001/A001192.seq | 87ee234142b92debb2d9aa54ed767cd4 |
A001193 | a(n) = (n+1)*(2*n)!/(2^n*n!) = (n+1)*(2n-1)!!. | [
"1",
"2",
"9",
"60",
"525",
"5670",
"72765",
"1081080",
"18243225",
"344594250",
"7202019825",
"164991726900",
"4111043861925",
"110681950128750",
"3201870700153125",
"99044533658070000",
"3262279327362680625",
"113987877673731311250",
"4211218814057295665625",
"164015890652757... | [
"nonn",
"easy"
] | 64 | 0 | 2 | [
"A001193",
"A059366",
"A167591",
"A167594"
] | [
"M1944",
"N0770"
] | N. J. A. Sloane | 2025-07-02T16:01:54 | oeisdata/seq/A001/A001193.seq | 82f86f6b5b304d1996da6afa02e0692a |
A001194 | a(n) = A059366(n,n-2) = A059366(n,2) for n >= 2, where the triangle A059366 arises in the expansion of a trigonometric integral. | [
"3",
"9",
"54",
"450",
"4725",
"59535",
"873180",
"14594580",
"273648375",
"5685805125",
"129636356850",
"3217338674550",
"86331921100425",
"2490343877896875",
"76844896803675000",
"2525635608280785000",
"88081541838792376875",
"3248654513701342370625"
] | [
"nonn"
] | 36 | 2 | 1 | null | [
"M2826",
"N1139"
] | N. J. A. Sloane | 2024-11-27T11:50:56 | oeisdata/seq/A001/A001194.seq | 37a858492680fe1b1ad77765c9055d52 |
A001195 | a(n) = floor(n*log((14/11)*n^(10/9))). | [
"0",
"2",
"4",
"7",
"10",
"13",
"16",
"20",
"24",
"27",
"31",
"36",
"40",
"44",
"48",
"53",
"57",
"62",
"66",
"71",
"76",
"80",
"85",
"90",
"95",
"100",
"105",
"110",
"115",
"120",
"125",
"130",
"136",
"141",
"146",
"152",
"157",
"162",
"16... | [
"nonn"
] | 16 | 1 | 2 | null | null | Herman H. Rosenfeld (herm3(AT)pacbell.net) | 2023-12-12T14:51:26 | oeisdata/seq/A001/A001195.seq | fe3db8e78476467653cfdf307c796049 |
A001196 | Double-bitters: only even length runs in binary expansion. | [
"0",
"3",
"12",
"15",
"48",
"51",
"60",
"63",
"192",
"195",
"204",
"207",
"240",
"243",
"252",
"255",
"768",
"771",
"780",
"783",
"816",
"819",
"828",
"831",
"960",
"963",
"972",
"975",
"1008",
"1011",
"1020",
"1023",
"3072",
"3075",
"3084",
"308... | [
"nonn",
"base",
"easy"
] | 101 | 0 | 2 | [
"A000695",
"A001196",
"A005823",
"A054238",
"A097252",
"A097262",
"A191108",
"A338086",
"A338754"
] | null | N. J. A. Sloane, based on an email from Bart la Bastide (bart(AT)xs4all.nl) | 2025-02-16T08:32:22 | oeisdata/seq/A001/A001196.seq | 8d9af7bb0ebf67510ad94491729c8621 |
A001197 | Zarankiewicz's problem k_2(n). | [
"4",
"7",
"10",
"13",
"17",
"22",
"25",
"30",
"35",
"40",
"46",
"53",
"57",
"62",
"68",
"75",
"82",
"89",
"97",
"106",
"109",
"116",
"123"
] | [
"nonn",
"hard",
"more"
] | 55 | 2 | 1 | [
"A001197",
"A001198",
"A006613",
"A006616",
"A006626",
"A072567",
"A339635",
"A347472",
"A350296",
"A376167"
] | [
"M3300",
"N1330"
] | N. J. A. Sloane | 2024-09-14T16:46:24 | oeisdata/seq/A001/A001197.seq | 4de30c5b6b131045695c9afc2ce9fc70 |
A001198 | Zarankiewicz's problem k_3(n). | [
"9",
"14",
"21",
"27",
"34",
"43",
"50",
"61",
"70",
"81",
"93",
"106",
"121",
"129"
] | [
"nonn",
"more",
"hard"
] | 38 | 3 | 1 | [
"A001197",
"A001198",
"A006613",
"A006626",
"A339635",
"A347473",
"A350237",
"A350304"
] | [
"M4601",
"N1962"
] | N. J. A. Sloane | 2022-10-18T13:04:44 | oeisdata/seq/A001/A001198.seq | bd50eaf8e344c9875379dd2c1877d4b1 |
A001199 | Erroneous version of A056642. | [
"1",
"1",
"2",
"6",
"32",
"353",
"8390",
"436399",
"50468754"
] | [
"dead"
] | 11 | 1 | 3 | null | [
"M1699",
"N0670"
] | null | 2010-06-01T03:00:00 | oeisdata/seq/A001/A001199.seq | fdefed4cd6c6d0c489d9c77d490baa9e |
A001200 | Number of linear geometries on n (unlabeled) points. | [
"1",
"1",
"1",
"2",
"3",
"5",
"10",
"24",
"69",
"384",
"5250",
"232929",
"28872973"
] | [
"nonn",
"hard",
"more",
"nice"
] | 53 | 0 | 4 | [
"A000041",
"A001200",
"A001548",
"A056642",
"A058731"
] | [
"M0726",
"N0271"
] | N. J. A. Sloane, D.Glynn(AT)math.canterbury.ac.nz | 2025-04-19T19:37:06 | oeisdata/seq/A001/A001200.seq | 05e4f91b495b9df4319a637ce6537878 |
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