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=", ")
CROSSREFS
KEYWORD
nonn
AUTHOR
David Consiglio, Jr., May 06 2021
STATUS
approved