A344808 Numbers that are the sum of six squares in four or more ways.

36, 41, 44, 45, 53, 54, 56, 57, 60, 62, 63, 65, 66, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115

Offset

1,1

Links

Sean A. Irvine, Table of n, a(n) for n = 1..1000

Example

41 = 1^2 + 1^2 + 1^2 + 1^2 + 1^2 + 6^2
   = 1^2 + 1^2 + 1^2 + 2^2 + 3^2 + 5^2
   = 1^2 + 2^2 + 3^2 + 3^2 + 3^2 + 3^2
   = 2^2 + 2^2 + 2^2 + 2^2 + 3^2 + 4^2
so 41 is a term.

Prog

(Python)
from itertools import combinations_with_replacement as cwr
from collections import defaultdict
keep = defaultdict(lambda: 0)
power_terms = [x**2 for x in range(1, 1000)]
for pos in cwr(power_terms, 6):
    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])

Crossrefs

Cf. A344797, A344807, A344809, A345481, A345513.

Sequence in context: A334911 A305942 A261265 * A295694 A295492 A225103

Adjacent sequences: A344805 A344806 A344807 * A344809 A344810 A344811

Keyword

nonn

Author

David Consiglio, Jr., Jun 20 2021

Status

approved