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.

A003294 Numbers k such that k^4 can be written as a sum of four positive 4th powers.

Original entry on oeis.org

353, 651, 706, 1059, 1302, 1412, 1765, 1953, 2118, 2471, 2487, 2501, 2604, 2824, 2829, 3177, 3255, 3530, 3723, 3883, 3906, 3973, 4236, 4267, 4333, 4449, 4557, 4589, 4942, 4949, 4974, 5002, 5208, 5281, 5295, 5463, 5491, 5543, 5648, 5658
Offset: 1

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Author

Keywords

Comments

Sequence gives solutions k to the Diophantine equation A^4 + B^4 + C^4 + D^4 = k^4.
Is this sequence the same as A096739? - David Wasserman, Nov 16 2007
A138760 (numbers k such that k^4 is a sum of 4th powers of four nonzero integers whose sum is k) is a subsequence. - Jonathan Sondow, Apr 06 2008

Examples

			353^4 = 30^4 + 120^4 + 272^4 + 315^4.
651^4 = 240^4 + 340^4 + 430^4 + 599^4.
2487^4 = 435^4 + 710^4 + 1384^4 + 2420^4.
2501^4 = 1130^4 + 1190^4 + 1432^4 + 2365^4.
2829^4 = 850^4 + 1010^4 + 1546^4 + 2745^4.
		

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • D. Wells, Curious and interesting numbers, Penguin Books, p. 139.

Crossrefs

Cf. A039664 (subsequence, primitive), A096739.
Cf. also A138760 (subsequence).

Programs

  • Mathematica
    fourthPowerSums = {};
    Do[a4 = a^4; Do[b4 = b^4; Do[c4 = c^4; Do[d4 = d^4; e4 = a4 + b4 + c4 + d4; e = Sqrt[Sqrt[e4]]; If[IntegerQ[e], AppendTo[fourthPowerSums, e]], {d, c + 1, 9000}], {c, b + 1, 6000}],{b, a + 1, 5000}], {a, 30, 3000}];
    Union @ fourthPowerSums (* Vladimir Joseph Stephan Orlovsky, May 19 2010 *)

Extensions

Corrected and extended by Don Reble, Jul 07 2007
More terms from David Wasserman, Nov 16 2007
Definition clarified by Jonathan Sondow, Apr 06 2008

A039664 Numbers k such that k^4 can be written as a sum of four positive 4th powers with no common factor.

Original entry on oeis.org

353, 651, 2487, 2501, 2829, 3723, 3973, 4267, 4333, 4449, 4949, 5281, 5463, 5491, 5543, 5729, 6167, 6609, 6801, 7101, 7209, 7339, 7703, 8373, 8433, 8493, 8517, 8577, 8637, 9137, 9243, 9431, 9519, 9639, 9797, 9877, 10419, 10939, 11681, 11757
Offset: 1

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Author

Keywords

Crossrefs

Cf. A003294 (nonprimitive solutions allowed), A096739.

Extensions

Edited by Don Reble, Jul 07 2007
Qualifier "positive" added to the name by Jianing Song, Jan 24 2020

A130022 Smallest natural number whose 4th power is the sum of n 4th powers of distinct natural numbers, or 0 if no such number exists.

Original entry on oeis.org

1, 0, 422481, 353, 15, 35, 25, 31, 37, 41, 35, 43, 39, 43, 47, 53, 55, 50, 50, 46, 48, 48, 50, 48, 50, 48, 52, 53, 55, 56, 54, 58, 58, 63, 65, 67, 70, 71, 73, 77, 81, 85, 87, 91, 93, 97, 101
Offset: 1

Views

Author

J. Lowell, Jun 15 2007

Keywords

Crossrefs

Cf. a(3) A003828, a(4) A096739, 3rd powers A130012, n-th powers A007666.

Extensions

More terms from Martin Fuller, Jul 06 2007

A138760 Numbers n such that n^4 is a sum of 4th powers of four nonzero integers whose sum is n.

Original entry on oeis.org

5491, 10982, 16473, 21964, 27455, 32946, 38437, 43928, 49419, 51361, 54910, 60401, 65892, 71383, 76874, 82365, 87856, 93347, 98838, 102722, 104329, 109820, 115311, 120802, 126293, 131784, 137275, 142766, 148257, 153748, 154083, 159239, 164730
Offset: 1

Views

Author

Jonathan Sondow, Mar 28 2008

Keywords

Comments

Any multiple of a member is also a member. A member that is not a multiple of another member is called primitive. Using elliptic curves, Jacobi and Madden prove that there are infinitely many primitive members. According to them, the only primitive members less than 222,000 are 5491 (due to Brudno) and 51361 (due to Wroblewski).

Examples

			5491^4 = 5400^4 + (-2634)^4 + 1770^4 + 955^4 and 5491 = 5400 - 2634 + 1770 + 955, so 5491 is a member (Brudno).
51361^4 = 48150^4 + (-31764)^4 + 27385^4 + 7590^4 and 51361 = 48150 - 31764 + 27385 + 7590, so 51361 is a member (Wroblewski).
1347505009^4 = 1338058950^4 + (-89913570)^4 + 504106884^4 + (-404747255)^4, and 1347505009 = 1338058950 - 89913570 + 504106884 - 404747255, so 1347505009 is a member (Jacobi-Madden).
		

Crossrefs

Formula

n^4 = a^4 + b^4 + c^4 + d^4 = (a+b+c+d)^4 with abcd =/= 0.

A239247 Numbers n such that n^4 can be written as a sum of five distinct positive 4th powers.

Original entry on oeis.org

15, 30, 35, 45, 55, 60, 65, 70, 75, 85, 89, 90, 95, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 165, 170, 175, 178, 180, 185, 190, 195, 205, 210, 215, 220, 225, 230, 233, 235, 240, 245, 250, 255, 260, 265, 267, 270, 275, 280, 285, 290, 295, 300
Offset: 1

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Author

Michel Marcus, Mar 13 2014

Keywords

Comments

Every multiple of a term is a term.

Examples

			15^4 = 4^4 + 6^4 + 8^4 + 9^4 + 14^4.
35^4 = 4^4 + 21^4 + 22^4 + 26^4 + 28^4.
55^4 = 2^4 + 13^4 + 16^4 + 44^4 + 48^4.
65^4 = 1^4 + 8^4 + 12^4 + 32^4 + 64^4.
85^4 = 2^4 + 13^4 + 32^4 + 34^4 + 84^4.
89^4 = 10^4 + 35^4 + 52^4 + 60^4 + 80^4.
95^4 = 6^4 + 48^4 + 66^4 + 67^4 + 78^4.
115^4 = 4^4 + 31^4 + 48^4 + 58^4 + 112^4.
125^4 = 8^4 + 11^4 + 26^4 + 84^4 + 118^4.
145^4 = 2^4 + 23^4 + 46^4 + 52^4 + 144^4.
155^4 = 6^4 + 39^4 + 88^4 + 96^4 + 144^4.
185^4 = 2^4 + 38^4 + 62^4 + 87^4 + 182^4.
205^4 = 4^4 + 133^4 + 142^4 + 146^4 + 156^4.
215^4 = 4^4 + 26^4 + 127^4 + 174^4 + 176^4.
233^4 = 40^4 + 65^4 + 94^4 + 150^4 + 220^4.
235^4 = 9^4 + 52^4 + 148^4 + 184^4 + 194^4.
		

Crossrefs

Cf. A130022, A003828 (three 4th powers), A096739 (four 4th powers).

Programs

  • PARI
    isok(n) = {ret = 0; for (x=1, sqrtnint(n^4\5, 4), for (y=x+1, sqrtnint((n^4 - x^4)\4, 4), for (z=y+1, sqrtnint((n^4 - x^4 - y^4)\3, 4), for (t=z+1, sqrtnint((n^4 - x^4 - y^4 - z^4)\2, 4), for (u=t+1, sqrtnint((n^4 - x^4 - y^4 - z^4 - t^4), 4), if (x^4+y^4+z^4+t^4+u^4 == n^4, print(n, ": ", x, ", ", y, ", ",z ,", ",t, ", ",u); ret = 1;);););););); return (ret);}

Formula

a(1) = A130022(4).

Extensions

Missing terms 15 and its multiples found by Alois P. Heinz, Mar 14 2014
More examples from Michel Marcus, Mar 18 2014
More terms from Lars Blomberg, Apr 05 2014

A134820 Primes in the sequence A003294 of certain fourth powers bases.

Original entry on oeis.org

353, 5281, 7703, 9137, 9431, 10939, 11681, 14029, 14489, 17519, 17881, 18077, 18701, 19483, 20719, 21013, 22247, 22961, 24953, 25589, 25913, 26821, 26987, 27893, 28297, 34327, 37273, 39671, 40031, 40129, 42209, 42359, 43397, 43781
Offset: 1

Views

Author

R. J. Mathar, Jan 28 2008

Keywords

Crossrefs

Formula

A003294 INTERSECT A000040
Showing 1-6 of 6 results.