A345581 Numbers that are the sum of eight fourth powers in six or more ways.

6723, 6788, 6853, 6898, 6963, 7028, 7938, 8003, 8068, 8178, 8243, 8308, 8483, 8963, 9043, 9173, 9218, 9283, 9348, 9413, 9493, 9523, 9668, 9763, 9828, 10003, 10132, 10258, 10277, 10307, 10372, 10628, 10708, 10738, 10788, 10803, 10868, 10933, 10948, 10978

Offset

1,1

Links

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

Example

6788 is a term because 6788 = 1^4 + 1^4 + 1^4 + 2^4 + 2^4 + 4^4 + 7^4 + 8^4 = 1^4 + 1^4 + 1^4 + 2^4 + 3^4 + 6^4 + 6^4 + 8^4 = 1^4 + 2^4 + 2^4 + 2^4 + 2^4 + 3^4 + 3^4 + 9^4 = 2^4 + 2^4 + 2^4 + 3^4 + 3^4 + 3^4 + 7^4 + 8^4 = 2^4 + 3^4 + 3^4 + 4^4 + 4^4 + 6^4 + 7^4 + 7^4 = 3^4 + 3^4 + 3^4 + 4^4 + 6^4 + 6^4 + 6^4 + 7^4.

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, 8):
    tot = sum(pos)
    keep[tot] += 1
    rets = sorted([k for k, v in keep.items() if v >= 6])
    for x in range(len(rets)):
        print(rets[x])

Crossrefs

Cf. A345536, A345572, A345580, A345582, A345590, A345614, A345838.

Sequence in context: A190292 A164972 A190129 * A345838 A237041 A031580

Adjacent sequences: A345578 A345579 A345580 * A345582 A345583 A345584

Keyword

nonn

Author

David Consiglio, Jr., Jun 20 2021

Status

approved