A345547 Numbers that are the sum of nine cubes in eight or more ways.

744, 770, 805, 818, 840, 842, 844, 847, 859, 861, 866, 868, 877, 880, 883, 887, 894, 896, 903, 908, 909, 910, 911, 913, 915, 916, 920, 922, 929, 935, 939, 940, 945, 946, 948, 950, 952, 954, 955, 957, 959, 961, 964, 965, 966, 971, 972, 973, 976, 978, 983, 985

Offset

1,1

Links

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

Example

770 is a term because 770 = 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 2^3 + 3^3 + 8^3 = 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 3^3 + 3^3 + 4^3 + 7^3 = 1^3 + 1^3 + 1^3 + 1^3 + 2^3 + 2^3 + 3^3 + 6^3 + 6^3 = 1^3 + 1^3 + 2^3 + 2^3 + 2^3 + 2^3 + 2^3 + 5^3 + 7^3 = 1^3 + 1^3 + 3^3 + 3^3 + 3^3 + 3^3 + 3^3 + 5^3 + 6^3 = 1^3 + 2^3 + 2^3 + 2^3 + 3^3 + 4^3 + 4^3 + 4^3 + 6^3 = 2^3 + 2^3 + 2^3 + 2^3 + 3^3 + 3^3 + 4^3 + 5^3 + 6^3 = 3^3 + 3^3 + 3^3 + 3^3 + 4^3 + 4^3 + 4^3 + 4^3 + 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 >= 8])
    for x in range(len(rets)):
        print(rets[x])

Crossrefs

Cf. A345505, A345538, A345546, A345548, A345556, A345592, A345800.

Sequence in context: A349677 A119595 A289141 * A345800 A331092 A235294

Adjacent sequences: A345544 A345545 A345546 * A345548 A345549 A345550

Keyword

nonn

Author

David Consiglio, Jr., Jun 20 2021

Status

approved