OFFSET
1,2
COMMENTS
Subsequence of A033950.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..5479 (terms below 10^9)
EXAMPLE
36/A000005(36) = 36/9 = 4 = 2^2, hence 36 is in the sequence.
MATHEMATICA
Select[Range[20000], IntegerQ[Sqrt[#/DivisorSigma[0, #]]]&] Harvey P. Dale, May 21 2012
PROG
(PARI) {m=18000; for(n=1, m, s=sigma(n, 0); if(n%s==0&&issquare(n/s), print1(n, ", ")))}
CROSSREFS
KEYWORD
nonn
AUTHOR
Ctibor O. Zizka, Oct 10 2008
EXTENSIONS
Edited and extended by Klaus Brockhaus, Oct 15 2008
STATUS
approved