OFFSET
1,2
LINKS
Ivan Neretin, Table of n, a(n) for n = 1..10000
MATHEMATICA
Select[Sqrt[DivisorSigma[1, Range@1800]], IntegerQ] (* Ivan Neretin, Jun 05 2015 *)
PROG
(PARI) lista(nn) = {for (n=1, nn, if (issquare(s=sigma(n)), print1(sqrtint(s), ", ")); ); } \\ Michel Marcus, Dec 18 2013
CROSSREFS
KEYWORD
nonn,look
AUTHOR
Labos Elemer, Aug 22 2002
STATUS
approved