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A343987
Numbers that are the sum of four positive cubes in five or more ways.
8
5105, 5131, 5616, 5859, 6435, 6883, 7777, 9315, 9737, 9793, 10017, 10250, 10458, 10936, 10962, 11000, 11060, 11088, 11592, 11664, 11781, 12168, 12229, 12285, 12320, 12385, 12392, 12411, 12707, 13104, 13384, 13734, 13832, 13904, 13923, 14112, 14183, 14239, 14581, 14833, 14896, 14904, 15176, 15561, 15596
OFFSET
1,1
LINKS
David Consiglio, Jr., Table of n, a(n) for n = 1..20000
EXAMPLE
5616 = 1^3 + 8^3 + 12^3 + 15^3
= 2^3 + 8^3 + 10^3 + 16^3
= 4^3 + 4^3 + 14^3 + 14^3
= 4^3 + 5^3 + 11^3 + 16^3
= 8^3 + 9^3 + 10^3 + 15^3
so 5616 is a term.
PROG
(Python)
from itertools import combinations_with_replacement as cwr
from collections import defaultdict
keep = defaultdict(lambda: 0)
power_terms = [x ** 3 for x in range(1, 50)]
for pos in cwr(power_terms, 4):
tot = sum(pos)
keep[tot] += 1
rets = sorted([k for k, v in keep.items() if v >= 5])
for x in range(len(rets)):
print(rets[x], end=", ")
KEYWORD
nonn
AUTHOR
STATUS
approved