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 1-5 of 5 results.

A025332 Numbers that are the sum of 3 nonzero squares in 4 or more ways.

Original entry on oeis.org

129, 134, 146, 153, 161, 171, 189, 194, 198, 201, 206, 209, 230, 234, 243, 246, 249, 251, 254, 257, 261, 266, 269, 270, 278, 281, 285, 290, 293, 294, 297, 299, 306, 314, 321, 326, 329, 339, 341, 342, 350, 353, 354, 362, 363, 365, 369, 371, 374, 378, 381, 386, 387, 389
Offset: 1

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Crossrefs

A343971 Numbers that are the sum of four positive cubes in four or more ways.

Original entry on oeis.org

1979, 2737, 3663, 4384, 4445, 4474, 4949, 5105, 5131, 5257, 5320, 5473, 5499, 5553, 5616, 5733, 5768, 5833, 5852, 5859, 6064, 6104, 6328, 6372, 6435, 6587, 6643, 6832, 6883, 6912, 6974, 7000, 7030, 7120, 7217, 7371, 7560, 7686, 7777, 7840, 8099, 8108, 8281, 8316, 8344, 8379, 8414, 8505, 8568, 8927, 9016, 9018
Offset: 1

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Author

David Consiglio, Jr., May 05 2021

Keywords

Examples

			3663 = 1^3 + 10^3 + 11^3 + 11^3
     = 2^3 +  4^3 +  6^3 + 15^3
     = 2^3 +  9^3 +  9^3 + 13^3
     = 4^3 +  7^3 +  8^3 + 14^3
so 3663 is a term.
		

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(1,50)]
    for pos in cwr(power_terms,4):
        tot = sum(pos)
        keep[tot] += 1
    rets = sorted([k for k,v in keep.items() if v >= 4])
    for x in range(len(rets)):
        print(rets[x])

A025368 Numbers that are the sum of 4 nonzero squares in 3 or more ways.

Original entry on oeis.org

28, 42, 52, 55, 58, 60, 63, 66, 67, 70, 73, 75, 76, 78, 79, 82, 84, 85, 87, 90, 91, 92, 93, 95, 97, 98, 99, 100, 102, 103, 105, 106, 108, 109, 110, 111, 112, 114, 115, 117, 118, 119, 121, 122, 123, 124, 125, 126, 127, 129, 130, 132, 133, 134, 135, 137, 138, 139, 140, 141
Offset: 1

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Formula

{n: A025428(n) >=3}. Union of A025369 and A025359.- R. J. Mathar, Jun 15 2018

A025370 Numbers that are the sum of 4 nonzero squares in 5 or more ways.

Original entry on oeis.org

82, 90, 100, 102, 103, 106, 108, 111, 114, 115, 117, 118, 122, 124, 126, 127, 130, 132, 133, 135, 138, 143, 145, 147, 148, 150, 151, 153, 154, 156, 157, 159, 162, 163, 165, 166, 167, 169, 170, 171, 172, 174, 175, 177, 178, 180, 181, 182, 183, 186, 187, 188, 189, 190
Offset: 1

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Crossrefs

Formula

{n: A025428(n) >= 5}. Union of A025371 and A025361. - R. J. Mathar, Jun 15 2018

A344797 Numbers that are the sum of five squares in four or more ways.

Original entry on oeis.org

53, 56, 59, 61, 62, 64, 67, 68, 70, 71, 72, 74, 75, 76, 77, 79, 80, 82, 83, 84, 85, 86, 88, 89, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126
Offset: 1

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Author

Sean A. Irvine, May 28 2021

Keywords

Crossrefs

Showing 1-5 of 5 results.