A141231 Positive integers whose prime factorizations contain only primes from A001122.

3, 5, 9, 11, 13, 15, 19, 25, 27, 29, 33, 37, 39, 45, 53, 55, 57, 59, 61, 65, 67, 75, 81, 83, 87, 95, 99, 101, 107, 111, 117, 121, 125, 131, 135, 139, 143, 145, 149, 159, 163, 165, 169, 171, 173, 177, 179, 181, 183, 185, 195, 197, 201, 209, 211, 225, 227, 243, 247, 249

Offset: 1

Author

Vladimir Shevelev, Jun 16 2008

Keywords

• nonn

Crossrefs

Cf. A001122, A000040.

Programs

Mathematica

aQ[n_] := Length[Select[FactorInteger[n][[;; , 1]], # > 1 && PrimitiveRoot@# != 2 &]] == 0; Select[Range[2, 250], aQ] (* Amiram Eldar, Dec 09 2018 *)

PARI

isokp(p) = znorder(Mod(2, p))==(p-1);
isok(n) = {if ((n>1) && (n % 2), my(f=factor(n)); #select(x->isokp(x), f[, 1]) == #f~; , 0); } \\ Michel Marcus, Dec 09 2018

Extensions

More terms from Michel Marcus, Dec 09 2018