A345150 Numbers that are the sum of four third powers in seven or more ways.

13104, 18928, 19376, 20755, 21203, 21896, 22743, 24544, 24570, 24787, 25172, 25928, 27720, 27755, 27846, 28917, 29582, 30429, 31031, 31248, 31339, 31402, 31528, 32858, 33579, 34056, 34624, 34713, 34776, 35289, 35317, 35441, 35497, 35712, 36162, 36190, 36225

Offset

1,1

Links

David Consiglio, Jr., Table of n, a(n) for n = 1..10000

Example

13104 is a term because 13104 = 1^3 + 10^3 + 16^3 + 18^3  = 1^3 + 11^3 + 14^3 + 19^3  = 2^3 + 9^3 + 15^3 + 19^3  = 4^3 + 6^3 + 14^3 + 20^3  = 4^3 + 9^3 + 10^3 + 21^3  = 5^3 + 7^3 + 11^3 + 21^3  = 8^3 + 9^3 + 14^3 + 19^3.

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, 1000)]
for pos in cwr(power_terms, 4):
    tot = sum(pos)
    keep[tot] += 1
rets = sorted([k for k, v in keep.items() if v >= 7])
for x in range(len(rets)):
    print(rets[x])

Crossrefs

Cf. A025372, A344922, A345086, A345148, A345151, A345152, A345180.

Sequence in context: A249495 A235335 A184768 * A345151 A252548 A015341

Adjacent sequences: A345147 A345148 A345149 * A345151 A345152 A345153

Keyword

nonn

Author

David Consiglio, Jr., Jun 09 2021

Status

approved