OFFSET
1,2
COMMENTS
a(10) > 10^12. - Giovanni Resta, Jun 10 2016
MATHEMATICA
Select[Range[150000], Mod[Plus @@ DivisorSigma[1, {#, #^2}], #] == 0 &] (* Giovanni Resta, Jun 10 2016 *)
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Alex Ratushnyak, Nov 28 2013
EXTENSIONS
a(6)-a(9) from Giovanni Resta, Jun 10 2016
STATUS
approved