cp's OEIS Frontend

A345574 Numbers that are the sum of seven fourth powers in eight or more ways.

%I A345574 #6 Jul 31 2021 17:58:11
%S A345574 19491,21252,21267,21332,21507,21636,21876,23652,25347,30372,31251,
%T A345574 31412,31652,32116,32356,33811,33907,35427,35637,35652,35892,36052,
%U A345574 36261,37812,37827,38052,38067,38596,38676,39267,39347,39891,39971,39972,40212,40356,40452
%N A345574 Numbers that are the sum of seven fourth powers in eight or more ways.
%H A345574 Sean A. Irvine, <a href="/A345574/b345574.txt">Table of n, a(n) for n = 1..10000</a>
%e A345574 21252 is a term because 21252 = 1^4 + 1^4 + 1^4 + 1^4 + 4^4 + 4^4 + 12^4 = 1^4 + 1^4 + 2^4 + 2^4 + 2^4 + 9^4 + 11^4 = 1^4 + 1^4 + 7^4 + 8^4 + 8^4 + 8^4 + 9^4 = 1^4 + 2^4 + 2^4 + 3^4 + 7^4 + 8^4 + 11^4 = 1^4 + 2^4 + 3^4 + 3^4 + 3^4 + 4^4 + 12^4 = 1^4 + 2^4 + 4^4 + 6^4 + 9^4 + 9^4 + 9^4 = 1^4 + 4^4 + 4^4 + 6^4 + 7^4 + 7^4 + 11^4 = 3^4 + 4^4 + 6^4 + 7^4 + 8^4 + 9^4 + 9^4.
%o A345574 (Python)
%o A345574 from itertools import combinations_with_replacement as cwr
%o A345574 from collections import defaultdict
%o A345574 keep = defaultdict(lambda: 0)
%o A345574 power_terms = [x**4 for x in range(1, 1000)]
%o A345574 for pos in cwr(power_terms, 7):
%o A345574     tot = sum(pos)
%o A345574     keep[tot] += 1
%o A345574     rets = sorted([k for k, v in keep.items() if v >= 8])
%o A345574     for x in range(len(rets)):
%o A345574         print(rets[x])
%Y A345574 Cf. A345526, A345565, A345573, A345575, A345583, A345630, A345830.
%K A345574 nonn
%O A345574 1,1
%A A345574 _David Consiglio, Jr._, Jun 20 2021