OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..600
MATHEMATICA
pnpfQ[n_]:=Module[{pn=PrimeNu[n], fi=Transpose[FactorInteger[n]][[2]]}, PrimeQ[ pn]&&Length[Union[fi]]==pn&&AllTrue[fi, PrimeQ]]; Select[Range[ 11000], pnpfQ] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Aug 12 2015 *)
PROG
(PARI) isok(n) = {nbf = omega(n); if (! isprime(nbf), return (0)); f = factor(n); for (i = 1, nbf, if (! isprime(f[i, 2]), return (0)); for (j = i+1, nbf, if (f[i, 2] == f[j, 2], return (0)); ); ); return (1); } \\ Michel Marcus, Aug 18 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Jon Wild, Feb 14 2006
EXTENSIONS
Definition clarified by Harvey P. Dale, Aug 12 2015
STATUS
approved