OFFSET
1,1
MATHEMATICA
p[n_]:=Module[{c=DivisorSigma[1, n]/DivisorSigma[0, n]}, If[PrimeQ[c], c, 0]]; nn=62000; With[{comps=Complement[Range[nn], Prime[Range[PrimePi[nn]]]]}, Select[ p/@comps, #!=0&]] (* Harvey P. Dale, Feb 19 2012 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Jun 17 2001
More terms from Sean A. Irvine, Jul 16 2021
STATUS
approved