cp's OEIS Frontend

A345571 Numbers that are the sum of seven fourth powers in five or more ways.

%I A345571 #6 Jul 31 2021 17:58:01
%S A345571 6642,6707,6772,6882,6947,7922,7987,8227,8962,9267,9507,9747,10116,
%T A345571 10291,10722,10787,10867,10932,10962,11331,11411,11571,12676,12851,
%U A345571 12916,13187,13252,13891,13956,14131,14211,14707,14772,14802,14917,14932,14947,15012,15092
%N A345571 Numbers that are the sum of seven fourth powers in five or more ways.
%H A345571 Sean A. Irvine, <a href="/A345571/b345571.txt">Table of n, a(n) for n = 1..10000</a>
%e A345571 6707 is a term because 6707 = 1^4 + 1^4 + 1^4 + 2^4 + 6^4 + 6^4 + 8^4 = 1^4 + 2^4 + 2^4 + 2^4 + 2^4 + 3^4 + 9^4 = 2^4 + 2^4 + 2^4 + 3^4 + 3^4 + 7^4 + 8^4 = 2^4 + 3^4 + 4^4 + 4^4 + 6^4 + 7^4 + 7^4 = 3^4 + 3^4 + 4^4 + 6^4 + 6^4 + 6^4 + 7^4.
%o A345571 (Python)
%o A345571 from itertools import combinations_with_replacement as cwr
%o A345571 from collections import defaultdict
%o A345571 keep = defaultdict(lambda: 0)
%o A345571 power_terms = [x**4 for x in range(1, 1000)]
%o A345571 for pos in cwr(power_terms, 7):
%o A345571     tot = sum(pos)
%o A345571     keep[tot] += 1
%o A345571     rets = sorted([k for k, v in keep.items() if v >= 5])
%o A345571     for x in range(len(rets)):
%o A345571         print(rets[x])
%Y A345571 Cf. A345523, A345562, A345570, A345572, A345580, A345608, A345827.
%K A345571 nonn
%O A345571 1,1
%A A345571 _David Consiglio, Jr._, Jun 20 2021