A345513 Numbers that are the sum of six cubes in four or more ways.

626, 830, 837, 856, 873, 891, 947, 954, 982, 1008, 1026, 1045, 1052, 1053, 1071, 1094, 1097, 1106, 1109, 1134, 1143, 1150, 1153, 1169, 1172, 1195, 1208, 1227, 1234, 1241, 1253, 1260, 1267, 1278, 1279, 1283, 1286, 1290, 1297, 1316, 1323, 1324, 1358, 1361, 1368

Offset

1,1

Links

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

Example

830 is a term because 830 = 1^3 + 1^3 + 2^3 + 3^3 + 3^3 + 8^3 = 1^3 + 3^3 + 3^3 + 5^3 + 5^3 + 6^3 = 1^3 + 3^3 + 3^3 + 3^3 + 4^3 + 7^3 = 2^3 + 2^3 + 3^3 + 3^3 + 6^3 + 6^3.

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, 6):
    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. A344034, A344808, A345512, A345514, A345522, A345561, A345766.

Sequence in context: A050448 A364073 A045171 * A345766 A158383 A031728

Adjacent sequences: A345510 A345511 A345512 * A345514 A345515 A345516

Keyword

nonn

Author

David Consiglio, Jr., Jun 20 2021

Status

approved