A345559 - OEIS

%I #6 Jul 31 2021 18:04:58

%S 261,276,291,341,356,421,516,531,596,771,885,900,965,1140,1361,1509,

%T 1556,1571,1636,1811,2180,2596,2611,2661,2676,2691,2706,2721,2741,

%U 2756,2771,2786,2836,2851,2916,2931,2946,2961,3011,3026,3091,3186,3201,3220,3266

%N Numbers that are the sum of six fourth powers in two or more ways.

%H Sean A. Irvine, <a href="/A345559/b345559.txt">Table of n, a(n) for n = 1..10000</a>

%e 276 is a term because 276 = 1^4 + 1^4 + 1^4 + 1^4 + 2^4 + 4^4 = 1^4 + 2^4 + 2^4 + 3^4 + 3^4 + 3^4.

%o (Python)

%o from itertools import combinations_with_replacement as cwr

%o from collections import defaultdict

%o keep = defaultdict(lambda: 0)

%o power_terms = [x**4 for x in range(1, 1000)]

%o for pos in cwr(power_terms, 6):

%o     tot = sum(pos)

%o     keep[tot] += 1

%o     rets = sorted([k for k, v in keep.items() if v >= 2])

%o     for x in range(len(rets)):

%o         print(rets[x])

%Y Cf. A003340, A344238, A345507, A345511, A345560, A345568, A345814.

%K nonn

%O 1,1

%A _David Consiglio, Jr._, Jun 20 2021