A345541 - OEIS

%I #6 Aug 05 2021 15:18:59

%S 72,133,140,147,159,161,166,168,175,182,185,187,189,194,196,198,201,

%T 203,205,208,213,217,220,222,224,227,231,238,239,243,245,246,250,252,

%U 257,259,261,264,265,266,271,273,276,278,280,283,285,287,289,290,292,294

%N Numbers that are the sum of nine cubes in two or more ways.

%H Sean A. Irvine, <a href="/A345541/b345541.txt">Table of n, a(n) for n = 1..10000</a>

%e 133 is a term because 133 = 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 4^3 = 1^3 + 1^3 + 2^3 + 2^3 + 2^3 + 2^3 + 2^3 + 3^3 + 3^3.

%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**3 for x in range(1, 1000)]

%o for pos in cwr(power_terms, 9):

%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. A003332, A345499, A345532, A345542, A345550, A345586, A345794.

%K nonn

%O 1,1

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