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A344730 Numbers that are the sum of three fourth powers in exactly seven ways. 6
779888018, 12478208288, 33038379458, 63170929458, 114872872562, 199651332608, 329296962722, 393006728738, 419200136082, 487430011250, 528614071328, 959702600738, 1010734871328, 1369390032738, 1502549262242, 1525400097858, 1653983981762, 1668273965442, 1756039197458, 1793250582818, 1837965960992, 1912768493202 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Differs from A344729 at term 2 because 5745705602 3^4+ 230^4+ 233^4 = 25^4+ 218^4+ 243^4 = 43^4+ 207^4+ 250^4 = 58^4+ 197^4+ 255^4 = 85^4+ 177^4+ 262^4 = 90^4+ 173^4+ 263^4 = 102^4+ 163^4+ 265^4 = 122^4+ 145^4+ 267^4

LINKS

Sean A. Irvine, Table of n, a(n) for n = 1..86

EXAMPLE

779888018 is a term because 779888018 = 3^4+ 139^4+ 142^4 = 9^4+ 38^4+ 167^4 = 14^4+ 133^4+ 147^4 = 43^4+ 114^4+ 157^4 = 47^4+ 111^4+ 158^4 = 63^4+ 98^4+ 161^4 = 73^4+ 89^4+ 162^4

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, 3):

    tot = sum(pos)

    keep[tot] += 1

rets = sorted([k for k, v in keep.items() if v == 7])

for x in range(len(rets)):

    print(rets[x])

CROSSREFS

Cf. A344648, A344729, A344738, A344923, A345085.

Sequence in context: A058420 A297867 A344729 * A225389 A166121 A046186

Adjacent sequences:  A344727 A344728 A344729 * A344731 A344732 A344733

KEYWORD

nonn

AUTHOR

David Consiglio, Jr., May 27 2021

STATUS

approved

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Last modified September 27 21:12 EDT 2021. Contains 347698 sequences. (Running on oeis4.)