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 1-7 of 7 results.

A294297 Integers with precisely five partitions into sums of four squares of nonnegative numbers.

Original entry on oeis.org

50, 52, 54, 58, 70, 73, 74, 75, 76, 84, 85, 86, 89, 91, 93, 101, 103, 109, 111, 113, 127, 131, 140, 142, 143, 151, 167, 191, 200, 208, 216, 232, 280, 296, 304, 336, 344, 560, 568, 800, 832, 864, 928, 1120, 1184, 1216, 1344, 1376, 2240, 2272, 3200, 3328, 3456
Offset: 1

Views

Author

Robert Price, Oct 27 2017

Keywords

Comments

A002635(a(n)) = 5.

Crossrefs

Programs

  • Mathematica
    f[n_] := Length@ PowersRepresentations[n, 4, 2]; Select[ Range@ 3500, f@# == 5 &] (* Robert G. Wilson v, Oct 27 2017 *)

A293175 Integers with precisely six partitions into sums of four squares of nonnegative numbers.

Original entry on oeis.org

66, 81, 97, 99, 105, 110, 115, 121, 123, 124, 137, 139, 141, 149, 155, 156, 158, 159, 164, 179, 188, 239, 264, 284, 440, 496, 624, 632, 656, 752, 1056, 1136, 1760, 1984, 2496, 2528, 2624, 3008, 4224, 4544, 7040, 7936, 9984, 10112, 10496, 12032, 16896, 18176
Offset: 1

Views

Author

Robert Price, Oct 27 2017

Keywords

Comments

A002635(a(n)) = 6.

Crossrefs

Programs

  • Mathematica
    f[n_] := Length@ PowersRepresentations[n, 4, 2]; Select[ Range@ 19000, f@# == 6 &] (* Robert G. Wilson v, Oct 27 2017 *)

A294308 Integers with precisely seven partitions into sums of four squares of nonnegative numbers.

Original entry on oeis.org

82, 98, 100, 102, 106, 108, 118, 125, 129, 132, 133, 134, 135, 161, 163, 173, 183, 197, 199, 204, 211, 212, 215, 236, 263, 328, 392, 400, 408, 424, 432, 472, 528, 536, 816, 848, 944, 1312, 1568, 1600, 1632, 1696, 1728, 1888, 2112, 2144, 3264, 3392, 3776
Offset: 1

Views

Author

Robert Price, Oct 27 2017

Keywords

Comments

A002635(a(n)) = 7.

Crossrefs

Programs

  • Mathematica
    f[n_]:=Length@PowersRepresentations[n, 4, 2]; Select[Range@650, f@#==7 &] (* Vincenzo Librandi, Oct 28 2017 *)

A294310 Integers with precisely nine partitions into sums of four squares of nonnegative numbers.

Original entry on oeis.org

90, 146, 166, 174, 185, 187, 205, 206, 207, 209, 219, 220, 221, 223, 231, 235, 251, 260, 271, 287, 316, 359, 360, 380, 584, 664, 696, 824, 880, 1040, 1264, 1440, 1520, 2336, 2656, 2784, 3296, 3520, 4160, 5056, 5760, 6080, 9344, 10624, 11136, 13184, 14080
Offset: 1

Views

Author

Robert Price, Oct 27 2017

Keywords

Comments

A002635(a(n)) = 9.

Crossrefs

Programs

  • Mathematica
    f[n_]:=Length@PowersRepresentations[n, 4, 2]; Select[Range@850, f@#==9 &] (* Vincenzo Librandi, Oct 28 2017 *)

A085625 Numbers that are the sum of 2 squares in exactly 2 ways.

Original entry on oeis.org

25, 50, 65, 85, 100, 125, 130, 145, 169, 170, 185, 200, 205, 221, 225, 250, 260, 265, 289, 290, 305, 338, 340, 365, 370, 377, 400, 410, 442, 445, 450, 481, 485, 493, 500, 505, 520, 530, 533, 545, 565, 578, 580, 585, 610, 629, 676, 680, 685, 689, 697, 730
Offset: 1

Views

Author

Hugo Pfoertner, Jul 09 2003

Keywords

Comments

Wells erroneously writes that this sequence begins as 50, 65, 85, 145, ... . - Stefano Spezia, Sep 07 2024

Examples

			a(3) = 65 because 65 = 8^2 + 1^2 = 7^2 + 4^2;
a(4) = 85 because 85 = 9^2 + 2^2 = 7^2 + 6^2.
		

References

  • David Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1986, Revised edition 1987. See p. 125.

Crossrefs

Programs

  • Mathematica
    Select[Range[730], Length[PowersRepresentations[#,2,2]]==2 &] (* Stefano Spezia, Sep 07 2024 *)

Formula

n such that A000161(n) = 2.

A294309 Integers with precisely eight partitions into sums of four squares of nonnegative numbers.

Original entry on oeis.org

114, 117, 122, 126, 145, 147, 148, 157, 165, 169, 172, 175, 177, 181, 190, 193, 203, 227, 233, 311, 456, 488, 504, 592, 688, 760, 1824, 1952, 2016, 2368, 2752, 3040, 7296, 7808, 8064, 9472, 11008, 12160, 29184, 31232, 32256, 37888, 44032, 48640
Offset: 1

Views

Author

Robert Price, Oct 27 2017

Keywords

Comments

A002635(a(n)) = 8.

Crossrefs

Programs

  • Mathematica
    f[n_]:=Length@PowersRepresentations[n, 4, 2]; Select[Range@850, f@#==8 &] (* Vincenzo Librandi, Oct 28 2017 *)

A294311 Integers with precisely ten partitions into sums of four squares of nonnegative numbers.

Original entry on oeis.org

130, 138, 153, 154, 171, 180, 182, 195, 196, 201, 213, 214, 217, 228, 229, 238, 241, 244, 247, 249, 253, 254, 257, 259, 269, 276, 277, 281, 295, 299, 303, 308, 317, 319, 332, 335, 347, 428, 431, 520, 552, 616, 720, 728, 784, 856, 912, 952, 976, 1016, 1104
Offset: 1

Views

Author

Robert Price, Oct 27 2017

Keywords

Comments

A002635(a(n)) = 10.

Crossrefs

Programs

  • Mathematica
    f[n_]:=Length@PowersRepresentations[n, 4, 2]; Select[Range@850, f@#==10 &] (* Vincenzo Librandi, Oct 28 2017 *)
Showing 1-7 of 7 results.