OFFSET
1,1
LINKS
MATHEMATICA
Select[Range[250000], If[# == 1, 1, DivisorSigma[1, Apply[Times, FactorInteger[#] /. {p_, e_} /; e > 0 :> Prime[PrimePi@ p + 1]^e] ]] == 2 DivisorSigma[1, #] &] (* Michael De Vlieger, Aug 27 2020 *)
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Aug 27 2020
STATUS
approved