A181669 Primes p of the form 6n-1 such that p-1 is a semiprime and p+2 is prime or prime squared.

5, 11, 23, 47, 59, 107, 167, 179, 227, 347, 359, 839, 1019, 1319, 1367, 1487, 1619, 2027, 2207, 2999, 3119, 3167, 3467, 4127, 4259, 4547, 4787, 4799, 5099, 5639, 5879, 6659, 6779, 6827, 7559, 8819, 10007, 10607, 11699, 12107, 12539, 14387, 14867, 15287, 15647

Offset: 1

Author

Giovanni Teofilatto, Nov 18 2010

Keywords

• nonn

Comments

Except term 7, same as A181602.

Programs

Mathematica

Select[6*Range[3000]-1,PrimeQ[#]&&PrimeOmega[#-1]==2&&AnyTrue[ {#+2,Sqrt[ #+2]},PrimeQ]&] (* Harvey P. Dale, Jul 01 2022 *)