OFFSET
1,1
COMMENTS
MATHEMATICA
With[{s = DeleteCases[Map[ToExpression[#] &, Import["https://oeis.org/A007691/b007691.txt", "Data"]], _?(Length[#] == 0 &)][[All, -1]]}, Select[s[[1 ;; 45]], Function[k, NoneTrue[Divisors[k], # DivisorSigma[1, #] == k &]]]] (* Michael De Vlieger, Sep 28 2021, using b-file at A007691 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Sep 26 2021
STATUS
approved