A345541 Numbers that are the sum of nine cubes in two or more ways.

72, 133, 140, 147, 159, 161, 166, 168, 175, 182, 185, 187, 189, 194, 196, 198, 201, 203, 205, 208, 213, 217, 220, 222, 224, 227, 231, 238, 239, 243, 245, 246, 250, 252, 257, 259, 261, 264, 265, 266, 271, 273, 276, 278, 280, 283, 285, 287, 289, 290, 292, 294

Offset

1,1

Links

Sean A. Irvine, Table of n, a(n) for n = 1..10000

Example

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.

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, 9):
    tot = sum(pos)
    keep[tot] += 1
    rets = sorted([k for k, v in keep.items() if v >= 2])
    for x in range(len(rets)):
        print(rets[x])

Crossrefs

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

Sequence in context: A143741 A227166 A250772 * A345794 A157336 A369333

Adjacent sequences: A345538 A345539 A345540 * A345542 A345543 A345544

Keyword

nonn

Author

David Consiglio, Jr., Jun 20 2021

Status

approved