A047723 Sum of 12 but no fewer nonzero fourth powers.

12, 27, 42, 57, 72, 92, 107, 122, 137, 152, 172, 187, 192, 202, 217, 232, 252, 267, 282, 297, 312, 332, 347, 362, 377, 392, 412, 427, 432, 442, 457, 472, 492, 497, 507, 522, 537, 552, 572, 587, 602, 617, 636, 652, 667, 672, 682, 697, 716, 732, 747, 762

Offset: 1

Author

Arlin Anderson (starship1(AT)gmail.com)

Keywords

• nonn

Links

• David A. Corneth, Table of n, a(n) for n = 1..13916 (terms <= 200000)

Crossrefs

Cf. A000583, A002377, A003346, A046044.

Programs

Python

from itertools import count, takewhile, combinations_with_replacement as mc
def aupto(limit):
    qd = list(takewhile(lambda x: x <= limit, (k**4 for k in count(1))))
    ss = [set(sum(c) for c in mc(qd, i)) for i in range(13)]
    for i in range(11, 0, -1): ss[12] -= ss[i]
    return sorted(s for s in ss[12] if s <= limit)
print(aupto(762)) # Michael S. Branicky, Dec 27 2021

Extensions

Typo in data corrected by D. S. McNeil, Aug 17 2010