A165947 Primes of the form 2q + 3 where q is composite.

11, 19, 23, 31, 43, 47, 53, 59, 67, 71, 73, 79, 83, 101, 103, 107, 113, 127, 131, 139, 151, 157, 163, 167, 173, 179, 191, 193, 199, 211, 223, 227, 233, 239, 241, 251, 263, 269, 271, 283, 293, 307, 311, 313, 331, 347, 353, 359, 367, 373, 379, 383, 409, 419, 421

Offset: 1

Author

Claudio Meller, Oct 01 2009

Keywords

• nonn
• easy

Links

• G. C. Greubel, Table of n, a(n) for n = 1..2500

Crossrefs

Cf. A002808, A129069.

Programs

Mathematica

Select[Table[If[PrimeQ[n],0,2n+3],{n,2,500}],PrimeQ]  (* Harvey P. Dale, Mar 25 2011 *)

PARI

lista(nn) = forcomposite(q=4, nn, if(isprime(p=2*q+3), print1(p, ", "))); \\ Altug Alkan, Apr 18 2016

Formula

A000040 \ { {2,3,5} U A089531}. - R. J. Mathar, Oct 28 2009