A345559 Numbers that are the sum of six fourth powers in two or more ways.

261, 276, 291, 341, 356, 421, 516, 531, 596, 771, 885, 900, 965, 1140, 1361, 1509, 1556, 1571, 1636, 1811, 2180, 2596, 2611, 2661, 2676, 2691, 2706, 2721, 2741, 2756, 2771, 2786, 2836, 2851, 2916, 2931, 2946, 2961, 3011, 3026, 3091, 3186, 3201, 3220, 3266

Offset

1,1

Links

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

Example

276 is a term because 276 = 1^4 + 1^4 + 1^4 + 1^4 + 2^4 + 4^4 = 1^4 + 2^4 + 2^4 + 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, 6):
    tot = sum(pos)
    keep[tot] += 1
    rets = sorted([k for k, v in keep.items() if v >= 2])
    for x in range(len(rets)):
        print(rets[x])

Crossrefs

Cf. A003340, A344238, A345507, A345511, A345560, A345568, A345814.

Sequence in context: A045026 A319727 A131071 * A345814 A131062 A079506

Adjacent sequences: A345556 A345557 A345558 * A345560 A345561 A345562

Keyword

nonn

Author

David Consiglio, Jr., Jun 20 2021

Status

approved