A345542 Numbers that are the sum of nine positive cubes in three or more ways.
224, 231, 238, 245, 250, 257, 259, 264, 271, 276, 278, 280, 283, 285, 287, 290, 292, 294, 297, 299, 301, 302, 309, 311, 313, 315, 316, 318, 320, 322, 327, 334, 335, 337, 339, 341, 346, 348, 350, 353, 355, 357, 362, 365, 372, 374, 376, 379, 381, 383, 386, 387
Offset: 1
Keywords
Examples
231 is a term because 231 = 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 2^3 + 5^3 = 1^3 + 1^3 + 1^3 + 1^3 + 2^3 + 3^3 + 3^3 + 3^3 + 3^3 = 1^3 + 1^3 + 2^3 + 2^3 + 2^3 + 2^3 + 2^3 + 3^3 + 4^3.
Links
- Sean A. Irvine, Table of n, a(n) for n = 1..10000
Programs
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Mathematica
Select[Range[400],Length[Select[PowersRepresentations[#,9,3],FreeQ[ #,0]&]]> 2&] (* Harvey P. Dale, Jan 04 2022 *)
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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 >= 3]) for x in range(len(rets)): print(rets[x])
Extensions
Definition corrected by Harvey P. Dale, Jan 04 2022
Comments