OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..1000
MATHEMATICA
f[n_] := Module[{p = Select[PrimitiveRootList[n], PrimeQ], m}, m = Length[p]; If[MemberQ[p, m] && PrimeQ[m], m, 0]]; Select[f /@ Range[3000], # > 0 &] (* Amiram Eldar, Sep 25 2021 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Sven Simon, Nov 07 2004
EXTENSIONS
Offset corrected and a(2) inserted by Amiram Eldar, Sep 25 2021
STATUS
approved