A344239 Numbers that are the sum of three fourth powers in three or more ways.

811538, 1733522, 2798978, 3750578, 4614722, 5978882, 6573938, 7303842, 8878898, 12771458, 12984608, 13760258, 14677362, 15601698, 15916082, 16196193, 17868242, 20621042, 21556178, 22349522, 22673378, 25190802, 25589858, 27736352, 29969282, 30623138, 33998258, 39765362, 41532498, 44048498

Offset

1,1

Links

David Consiglio, Jr., Table of n, a(n) for n = 1..14213

Example

2798978 =  6^4 + 31^4 + 37^4
        =  9^4 + 29^4 + 38^4
        = 13^4 + 26^4 + 39^4
so 2798978 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, 3):
    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. A025398, A309762, A344240, A344241, A344277.

Sequence in context: A178290 A083617 A343082 * A344240 A238522 A372300

Adjacent sequences: A344236 A344237 A344238 * A344240 A344241 A344242

Keyword

nonn,changed

Author

David Consiglio, Jr., May 12 2021

Status

approved