A346279 Numbers that are the sum of seven fifth powers in exactly two ways.

4099, 4130, 4161, 4341, 4372, 4583, 5122, 5153, 5364, 6145, 7223, 7254, 7465, 8246, 10347, 11874, 11905, 12116, 12897, 14998, 19649, 20905, 20936, 21147, 21928, 24029, 28680, 36866, 36897, 37108, 37711, 37889, 39990, 40138, 44641, 51393, 51448, 51479, 51510

Offset

1,1

Comments

Differs from A345605 at term 156 because 84457 = 2^5 + 4^5 + 4^5 + 6^5 + 6^5 + 6^5 + 9^5 = 1^5 + 3^5 + 5^5 + 6^5 + 6^5 + 8^5 + 8^5 = 1^5 + 3^5 + 4^5 + 7^5 + 7^5 + 7^5 + 8^5.

Links

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

Example

4099 is a term because 4099 = 1^5 + 1^5 + 3^5 + 3^5 + 3^5 + 3^5 + 5^5 = 1^5 + 1^5 + 1^5 + 4^5 + 4^5 + 4^5 + 4^5.

Prog

(Python)
from itertools import combinations_with_replacement as cwr
from collections import defaultdict
keep = defaultdict(lambda: 0)
power_terms = [x**5 for x in range(1, 1000)]
for pos in cwr(power_terms, 7):
    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. A345605, A345824, A346278, A346280, A346327, A346357.

Sequence in context: A282548 A253712 A345605 * A023354 A226694 A345610

Adjacent sequences: A346276 A346277 A346278 * A346280 A346281 A346282

Keyword

nonn

Author

David Consiglio, Jr., Jul 13 2021

Status

approved