A345543 Numbers that are the sum of nine cubes in four or more ways.

224, 257, 264, 283, 320, 348, 355, 372, 374, 376, 381, 383, 390, 400, 402, 407, 409, 411, 413, 414, 416, 428, 435, 439, 442, 446, 450, 453, 454, 461, 465, 472, 474, 476, 479, 481, 486, 488, 491, 498, 500, 502, 503, 505, 507, 509, 510, 512, 514, 517, 519, 524

Offset

1,1

Links

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

Example

257 is a term because 257 = 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 4^3 + 4^3 = 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 2^3 + 3^3 + 5^3 = 1^3 + 1^3 + 1^3 + 2^3 + 3^3 + 3^3 + 3^3 + 3^3 + 3^3 = 1^3 + 2^3 + 2^3 + 2^3 + 2^3 + 2^3 + 3^3 + 3^3 + 4^3.

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 >= 4])
    for x in range(len(rets)):
        print(rets[x])

Crossrefs

Cf. A345501, A345534, A345542, A345544, A345552, A345588, A345796.

Sequence in context: A296896 A050241 A345542 * A345796 A046296 A240529

Adjacent sequences: A345540 A345541 A345542 * A345544 A345545 A345546

Keyword

nonn

Author

David Consiglio, Jr., Jun 20 2021

Status

approved