OFFSET
1,5
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..10000
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