A345597 Numbers that are the sum of ten fourth powers in four or more ways.

1620, 2660, 2725, 2740, 2835, 2855, 2870, 2900, 2915, 2920, 2935, 2950, 2965, 2980, 3000, 3015, 3030, 3045, 3095, 3110, 3160, 3175, 3190, 3205, 3220, 3240, 3255, 3270, 3285, 3335, 3350, 3415, 3430, 3445, 3460, 3479, 3510, 3525, 3544, 3559, 3574, 3589, 3639

Offset: 1

Author

David Consiglio, Jr., Jun 20 2021

Keywords

• nonn

Examples

			2660 is a term because 2660 = 1^4 + 1^4 + 1^4 + 1^4 + 2^4 + 2^4 + 2^4 + 2^4 + 6^4 + 6^4 = 1^4 + 1^4 + 1^4 + 3^4 + 4^4 + 4^4 + 4^4 + 4^4 + 4^4 + 6^4 = 1^4 + 2^4 + 2^4 + 2^4 + 2^4 + 2^4 + 2^4 + 3^4 + 3^4 + 7^4 = 2^4 + 3^4 + 3^4 + 3^4 + 3^4 + 4^4 + 4^4 + 4^4 + 4^4 + 6^4.
		

Links

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

Crossrefs

Cf. A345552, A345588, A345596, A345598, A345636, A345856.

Programs

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, 10):
    tot = sum(pos)
    keep[tot] += 1
    rets = sorted([k for k, v in keep.items() if v >= 4])
    for x in range(len(rets)):
        print(rets[x])