A343968 Numbers that are the sum of three positive cubes in four or more ways.

13896, 40041, 44946, 52200, 53136, 58995, 76168, 82278, 93339, 94184, 105552, 110683, 111168, 112384, 112832, 113400, 143424, 149416, 149904, 161568, 167616, 169560, 171296, 175104, 196776, 197569, 208144, 216126, 221696, 222984, 224505, 235808, 240813, 252062, 255312, 262683, 262781, 266031

Offset

1,1

Links

David Consiglio, Jr., Table of n, a(n) for n = 1..20000

Example

44946 =  7^3 + 12^3 + 35^3
      =  9^3 + 17^3 + 34^3
      = 11^3 + 24^3 + 31^3
      = 16^3 + 17^3 + 33^3
so 44946 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, 3):
    tot = sum(pos)
    keep[tot] += 1
rets = sorted([k for k, v in keep.items() if v >= 4])
for x in range(len(rets)):
    print(rets[x])

Crossrefs

Cf. A023051, A025332, A025398, A343967, A343969, A343971, A344277.

Sequence in context: A109483 A237941 A343085 * A343969 A190817 A298428

Adjacent sequences: A343965 A343966 A343967 * A343969 A343970 A343971

Keyword

nonn

Author

David Consiglio, Jr., May 05 2021

Status

approved