cp's OEIS Frontend

A345608 Numbers that are the sum of seven fifth powers in five or more ways.

%I A345608 #6 Jul 31 2021 16:25:18
%S A345608 6768576,6776120,7883668,8625376,8740709,10036201,10604054,12476826,
%T A345608 12618493,13006575,13060213,13080706,13174250,13536416,13550162,
%U A345608 13562501,13662500,14110656,14583968,15169276,15247994,16053313,16060683,16374218,16573507,16600001
%N A345608 Numbers that are the sum of seven fifth powers in five or more ways.
%H A345608 Sean A. Irvine, <a href="/A345608/b345608.txt">Table of n, a(n) for n = 1..4721</a>
%e A345608 6776120 is a term because 6776120 = 2^5 + 4^5 + 7^5 + 12^5 + 17^5 + 18^5 + 20^5 = 3^5 + 6^5 + 6^5 + 12^5 + 14^5 + 18^5 + 21^5 = 4^5 + 6^5 + 8^5 + 11^5 + 13^5 + 16^5 + 22^5 = 4^5 + 7^5 + 7^5 + 7^5 + 16^5 + 19^5 + 20^5 = 5^5 + 6^5 + 6^5 + 8^5 + 16^5 + 19^5 + 20^5.
%o A345608 (Python)
%o A345608 from itertools import combinations_with_replacement as cwr
%o A345608 from collections import defaultdict
%o A345608 keep = defaultdict(lambda: 0)
%o A345608 power_terms = [x**5 for x in range(1, 1000)]
%o A345608 for pos in cwr(power_terms, 7):
%o A345608     tot = sum(pos)
%o A345608     keep[tot] += 1
%o A345608     rets = sorted([k for k, v in keep.items() if v >= 5])
%o A345608     for x in range(len(rets)):
%o A345608         print(rets[x])
%Y A345608 Cf. A345571, A345607, A345609, A345613, A345719, A346282.
%K A345608 nonn
%O A345608 1,1
%A A345608 _David Consiglio, Jr._, Jun 20 2021