login
A050448
a(n) = Sum_{d|n, d==1 (mod 4)} d^4.
2
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
1,5
LINKS
MATHEMATICA
a[n_] := DivisorSum[n, #^4 &, Mod[#, 4] == 1 &]; Array[a, 50] (* Amiram Eldar, Jul 08 2023 *)
PROG
(PARI) a(n) = sumdiv(n, d, if ((d%4)==1, d^4)); \\ Michel Marcus, Aug 16 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 23 1999
EXTENSIONS
Offset corrected by Sean A. Irvine, Aug 15 2021
STATUS
approved