cp's OEIS Frontend

A345789 Numbers that are the sum of eight cubes in exactly seven ways.

%I A345789 #6 Jul 31 2021 22:37:24
%S A345789 902,908,921,938,958,963,982,991,996,1003,1008,1010,1017,1019,1028,
%T A345789 1029,1033,1047,1055,1058,1061,1062,1070,1087,1091,1094,1096,1097,
%U A345789 1104,1108,1111,1113,1115,1116,1118,1120,1122,1123,1127,1134,1141,1143,1145,1152,1153
%N A345789 Numbers that are the sum of eight cubes in exactly seven ways.
%C A345789 Differs from A345537 at term 7 because 970 = 1^3 + 1^3 + 1^3 + 1^3 + 4^3 + 6^3 + 7^3 + 7^3  = 1^3 + 1^3 + 2^3 + 2^3 + 2^3 + 6^3 + 6^3 + 8^3  = 1^3 + 1^3 + 5^3 + 5^3 + 5^3 + 5^3 + 5^3 + 7^3  = 1^3 + 2^3 + 2^3 + 2^3 + 3^3 + 4^3 + 5^3 + 9^3  = 1^3 + 2^3 + 3^3 + 5^3 + 5^3 + 5^3 + 6^3 + 7^3  = 1^3 + 3^3 + 4^3 + 4^3 + 4^3 + 4^3 + 7^3 + 7^3  = 2^3 + 2^3 + 3^3 + 3^3 + 5^3 + 6^3 + 6^3 + 7^3  = 2^3 + 2^3 + 4^3 + 4^3 + 4^3 + 5^3 + 5^3 + 8^3.
%C A345789 Likely finite.
%H A345789 Sean A. Irvine, <a href="/A345789/b345789.txt">Table of n, a(n) for n = 1..174</a>
%e A345789 908 is a term because 908 = 1^3 + 1^3 + 2^3 + 2^3 + 2^3 + 3^3 + 6^3 + 7^3 = 1^3 + 1^3 + 2^3 + 4^3 + 4^3 + 5^3 + 5^3 + 5^3 = 1^3 + 2^3 + 2^3 + 3^3 + 5^3 + 5^3 + 5^3 + 5^3 = 1^3 + 3^3 + 3^3 + 3^3 + 3^3 + 4^3 + 4^3 + 7^3 = 2^3 + 2^3 + 3^3 + 3^3 + 3^3 + 4^3 + 6^3 + 6^3 = 2^3 + 3^3 + 3^3 + 3^3 + 3^3 + 3^3 + 5^3 + 7^3 = 3^3 + 3^3 + 3^3 + 4^3 + 4^3 + 4^3 + 4^3 + 5^3.
%o A345789 (Python)
%o A345789 from itertools import combinations_with_replacement as cwr
%o A345789 from collections import defaultdict
%o A345789 keep = defaultdict(lambda: 0)
%o A345789 power_terms = [x**3 for x in range(1, 1000)]
%o A345789 for pos in cwr(power_terms, 8):
%o A345789     tot = sum(pos)
%o A345789     keep[tot] += 1
%o A345789     rets = sorted([k for k, v in keep.items() if v == 7])
%o A345789     for x in range(len(rets)):
%o A345789         print(rets[x])
%Y A345789 Cf. A345537, A345779, A345788, A345790, A345799, A345839.
%K A345789 nonn
%O A345789 1,1
%A A345789 _David Consiglio, Jr._, Jun 26 2021