OFFSET
1,3
COMMENTS
This was formerly A001481.
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
J. Touchard, On prime numbers and perfect numbers, Scripta Math., 129 (1953), 35-39. [Annotated scanned copy]
MAPLE
S:=(n, e)->add(k^e*sigma(k)*sigma(n-k), k=1..n-1); f:=e->[seq(S(n, e), n=1..30)]; f(8);
PROG
(PARI) a(n) = sum(k=1, n-1, k^8*sigma(k)*sigma(n-k)) \\ Colin Barker, Jul 16 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jul 03 2015
STATUS
approved