OFFSET
1,1
COMMENTS
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
MATHEMATICA
perfectPowerQ[n_] := n == 1 || GCD @@ FactorInteger[n][[All, 2]] > 1; Select[ Range@ 35000, perfectPowerQ[ #] && GCD[#, DivisorSigma[1, #]] > 1 &]
PROG
(PARI) for(n=1, 1e5, if(ispower(n), if(gcd(n, sigma(n)) > 1, print1(n, ", ")))) \\ Felix Fröhlich, Oct 25 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Robert G. Wilson v, Sep 29 2014
STATUS
approved