OFFSET
1,1
COMMENTS
MATHEMATICA
Select[Range[100]^2, Mod[DivisorSigma[1, If[# == 1, 1, Apply[Times, Flatten@ Map[Function[{p, e}, Map[Prime[Log2@# + 1]^(2^(PrimePi@ p - 1)) &, DeleteCases[NumberExpand[e, 2], 0]]] @@ # &, FactorInteger[#]]]]], 4] == 2 &] (* Michael De Vlieger, Feb 08 2020 *)
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Feb 03 2020
STATUS
approved