OFFSET
1,2
EXAMPLE
345 is in the sequence since sigma_3(345) = 6552^2 is a square.
MATHEMATICA
Select[Range[10^5], IntegerQ[ Sqrt[ DivisorSigma[3, #] ] ] &] (* Amiram Eldar, Dec 06 2018 *)
PROG
(PARI) for(n=1, 10^5, if(issquare(sigma(n, 3)), print1(n, ", ")))
CROSSREFS
KEYWORD
nonn
AUTHOR
Jason Earls, Aug 21 2001
EXTENSIONS
More terms from Thomas Baruchel, Oct 20 2003
More terms from Sean A. Irvine, Sep 24 2009
a(24)-a(26) from Amiram Eldar, Dec 06 2018
STATUS
approved