OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Perfect Powers.
Eric Weisstein's World of Mathematics, Divisor Function.
MAPLE
N:= 10^4: # to use all perfect powers <= N
L:= sort(convert({seq(seq(i^k, i=1..floor(N^(1/k))), k=2..ilog2(N))}, list)):
map(numtheory:-sigma, L); # Robert Israel, Oct 02 2014
PROG
(PARI) lista(nn) = {for (n=1, nn, if ((n==1) || ispower(n), print1(sigma(n), ", ")); ); } \\ Michel Marcus, Oct 02 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Oct 09 2002
STATUS
approved