A345845 Numbers that are the sum of nine fourth powers in exactly three ways.

519, 534, 599, 774, 1143, 1364, 1539, 1604, 1619, 1814, 2579, 2644, 2659, 2679, 2694, 2709, 2724, 2739, 2754, 2759, 2774, 2789, 2819, 2834, 2839, 2869, 2884, 2899, 2994, 2999, 3079, 3109, 3124, 3139, 3303, 3318, 3333, 3334, 3363, 3364, 3379, 3383, 3398, 3463

Offset

1,1

Comments

Differs from A345587 at term 26 because 285.

Links

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

Example

534 is a term because 534 = 1^4 + 1^4 + 1^4 + 1^4 + 1^4 + 1^4 + 2^4 + 4^4 + 4^4 = 1^4 + 1^4 + 1^4 + 2^4 + 2^4 + 3^4 + 3^4 + 3^4 + 4^4 = 2^4 + 2^4 + 2^4 + 3^4 + 3^4 + 3^4 + 3^4 + 3^4 + 3^4.

Prog

(Python)
from itertools import combinations_with_replacement as cwr
from collections import defaultdict
keep = defaultdict(lambda: 0)
power_terms = [x**4 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])

Crossrefs

Cf. A345587, A345795, A345835, A345844, A345846, A345855, A346338.

Sequence in context: A293085 A173791 A345587 * A051983 A250768 A043626

Adjacent sequences: A345842 A345843 A345844 * A345846 A345847 A345848

Keyword

nonn

Author

David Consiglio, Jr., Jun 26 2021

Status

approved