A003339 Numbers that are the sum of 5 positive 4th powers.
5, 20, 35, 50, 65, 80, 85, 100, 115, 130, 145, 165, 180, 195, 210, 245, 260, 275, 290, 305, 320, 325, 340, 355, 370, 385, 405, 420, 435, 450, 500, 515, 530, 545, 560, 580, 595, 610, 625, 629, 644, 659, 674, 675, 689, 690, 709, 724, 739, 754, 755, 770, 785, 789, 800
Offset: 1
Examples
From _David A. Corneth_, Aug 04 2020: (Start) 22418 is in the sequence as 22418 = 1^4 + 2^4 + 7^4 + 10^4 + 10^4. 30004 is in the sequence as 30004 = 2^4 + 3^4 + 5^4 + 11^4 + 11^4. 39028 is in the sequence as 39028 = 5^4 + 5^4 + 7^4 + 11^4 + 12^4. (End)
Links
- David A. Corneth, Table of n, a(n) for n = 1..10000 (first 1000 terms from T. D. Noe)
- Eric Weisstein's World of Mathematics, Biquadratic Number.
Crossrefs
Programs
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Mathematica
Select[Range[1000], AnyTrue[PowersRepresentations[#, 5, 4], First[#]>0&]&] (* Jean-François Alcover, Jul 18 2017 *)
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Python
from itertools import combinations_with_replacement as combs_with_rep def aupto(limit): qd = [k**4 for k in range(1, int(limit**.25)+2) if k**4 + 4 <= limit] ss = set(sum(c) for c in combs_with_rep(qd, 5)) return sorted(s for s in ss if s <= limit) print(aupto(800)) # Michael S. Branicky, May 20 2021