A344241 Numbers that are the sum of four fourth powers in three or more ways.

16578, 43234, 49329, 53218, 54978, 57154, 93393, 106354, 107649, 108754, 138258, 151219, 160434, 168963, 173539, 177699, 178738, 181138, 183603, 185298, 195378, 195859, 196418, 197154, 197778, 201683, 202419, 209763, 211249, 216594, 217138, 223074, 234274, 235554, 235569, 236674, 237249, 237699

Offset

1,1

Links

David Consiglio, Jr., Table of n, a(n) for n = 1..20000

Example

49329 = 2^4 + 2^4 + 12^4 + 13^4
      = 4^4 + 8^4 +  9^4 + 14^4
      = 6^4 + 9^4 + 12^4 + 12^4
so 49329 is a term of this sequence.

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, 50)]
for pos in cwr(power_terms, 4):
    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. A025407, A309763, A344239, A344242, A344243, A344352, A345337.

Sequence in context: A240901 A234894 A283028 * A344242 A234374 A234380

Adjacent sequences: A344238 A344239 A344240 * A344242 A344243 A344244

Keyword

nonn

Author

David Consiglio, Jr., May 12 2021

Status

approved