cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-6 of 6 results.

A025337 Numbers that are the sum of 3 nonzero squares in 9 or more ways.

Original entry on oeis.org

594, 614, 626, 689, 734, 761, 774, 794, 801, 846, 854, 866, 881, 909, 914, 926, 929, 941, 950, 965, 974, 986, 989, 990, 1001, 1025, 1026, 1034, 1041, 1046, 1049, 1062, 1070, 1074, 1089, 1091, 1097, 1106, 1109, 1118, 1121, 1130, 1134, 1139, 1154, 1161, 1166
Offset: 1

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Crossrefs

A345146 Numbers that are the sum of four third powers in nine or more ways.

Original entry on oeis.org

21896, 36225, 42120, 46683, 46872, 48321, 48825, 50806, 50904, 51408, 51480, 51506, 51688, 52208, 52416, 53200, 53865, 54971, 55575, 56385, 57113, 58338, 58968, 59059, 60480, 60515, 60984, 62244, 62433, 65303, 66024, 66276, 66339, 66430, 67158, 67536, 67851
Offset: 1

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Author

David Consiglio, Jr., Jun 09 2021

Keywords

Examples

			42120 is a term because 42120 = 1^3 + 19^3 + 22^3 + 27^3  = 2^3 + 3^3 + 13^3 + 33^3  = 2^3 + 6^3 + 17^3 + 32^3  = 3^3 + 3^3 + 20^3 + 31^3  = 3^3 + 17^3 + 20^3 + 29^3  = 3^3 + 13^3 + 14^3 + 32^3  = 6^3 + 15^3 + 16^3 + 31^3  = 7^3 + 17^3 + 23^3 + 27^3  = 11^3 + 13^3 + 21^3 + 29^3.
		

Crossrefs

Programs

  • Python
    from itertools import combinations_with_replacement as cwr
    from collections import defaultdict
    keep = defaultdict(lambda: 0)
    power_terms = [x**3 for x in range(1, 1000)]
    for pos in cwr(power_terms, 4):
        tot = sum(pos)
        keep[tot] += 1
    rets = sorted([k for k, v in keep.items() if v >= 9])
    for x in range(len(rets)):
        print(rets[x])

A025375 Numbers that are the sum of 4 nonzero squares in 10 or more ways.

Original entry on oeis.org

198, 202, 210, 234, 246, 247, 250, 252, 255, 258, 262, 268, 270, 273, 274, 279, 282, 285, 290, 292, 294, 295, 297, 298, 300, 301, 303, 306, 307, 310, 313, 315, 318, 319, 322, 324, 325, 327, 330, 333, 335, 338, 339, 340, 342, 343, 345, 346, 348, 350, 351, 354, 355, 357
Offset: 1

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Formula

{n: A025428(n) >= 10}. - R. J. Mathar, Jun 15 2018

A025373 Numbers that are the sum of 4 nonzero squares in 8 or more ways.

Original entry on oeis.org

130, 138, 150, 154, 162, 175, 178, 180, 186, 195, 196, 198, 202, 207, 210, 213, 214, 217, 218, 220, 222, 223, 225, 226, 228, 230, 231, 234, 235, 237, 238, 242, 243, 244, 246, 247, 250, 252, 253, 255, 258, 259, 262, 265, 266, 267, 268, 270, 271, 273, 274, 275, 276, 277
Offset: 1

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Crossrefs

Programs

  • Mathematica
    selQ[n_] := Length[ Select[ PowersRepresentations[n, 4, 2], Times @@ # != 0 &]] >= 8; Select[ Range[300], selQ] (* Jean-François Alcover, Oct 03 2013 *)

Formula

{n: A025428(n) >= 8}. - R. J. Mathar, Jun 15 2018

A344802 Numbers that are the sum of five squares in nine or more ways.

Original entry on oeis.org

101, 107, 109, 112, 115, 116, 118, 125, 127, 128, 131, 133, 134, 136, 139, 140, 142, 144, 146, 147, 148, 149, 151, 152, 154, 155, 157, 158, 159, 160, 161, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 178, 179, 180, 181, 182, 183, 184
Offset: 1

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Author

Sean A. Irvine, May 29 2021

Keywords

Crossrefs

A025393 Numbers that are the sum of 4 distinct nonzero squares in 9 or more ways.

Original entry on oeis.org

270, 286, 294, 306, 315, 318, 330, 334, 342, 345, 350, 351, 354, 366, 374, 375, 378, 382, 386, 390, 398, 399, 402, 405, 406, 410, 414, 417, 422, 426, 429, 430, 434, 435, 438, 441, 442, 446, 447, 450, 454, 455, 459, 462, 465, 466, 470, 471, 474, 477, 478, 482, 483, 485
Offset: 1

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Crossrefs

Formula

{n: A025443(n) >= 9}. - R. J. Mathar, Jun 15 2018
Showing 1-6 of 6 results.