A050448 a(n) = Sum_{d|n, d==1 (mod 4)} d^4.

1, 1, 1, 1, 626, 1, 1, 1, 6562, 626, 1, 1, 28562, 1, 626, 1, 83522, 6562, 1, 626, 194482, 1, 1, 1, 391251, 28562, 6562, 1, 707282, 626, 1, 1, 1185922, 83522, 626, 6562, 1874162, 1, 28562, 626, 2825762, 194482, 1, 1, 4107812, 1, 1, 1

Offset: 1

Author

N. J. A. Sloane, Dec 23 1999

Keywords

• nonn

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A001159, A050449, A050450, A050451.

Programs

Mathematica

a[n_] := DivisorSum[n, #^4 &, Mod[#, 4] == 1 &]; Array[a, 50] (* Amiram Eldar, Jul 08 2023 *)

PARI

a(n) = sumdiv(n, d, if ((d%4)==1, d^4)); \\ Michel Marcus, Aug 16 2021

Extensions

Offset corrected by Sean A. Irvine, Aug 15 2021