A067466 Primes p such that p-1 has 2 distinct prime factors.

7, 11, 13, 19, 23, 29, 37, 41, 47, 53, 59, 73, 83, 89, 97, 101, 107, 109, 113, 137, 149, 163, 167, 173, 179, 193, 197, 227, 233, 251, 263, 269, 293, 317, 347, 353, 359, 383, 389, 401, 433, 449, 467, 479, 487, 503, 509, 557, 563, 569, 577, 587, 593, 641, 653

Offset: 1

Author

Benoit Cloitre, Feb 23 2002

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A006093, A007774, A008334.

Programs

Mathematica

Select[Prime[Range[120]], PrimeNu[#-1] == 2 &] (* Amiram Eldar, Jun 06 2022 *)

PARI

lista(nn) = {forprime(p=1, nn, if (omega(p-1) == 2, print1(p, ", ")););} \\ Michel Marcus, Nov 22 2013