A129069 Numbers k such that (k-3)/2 is prime.

7, 9, 13, 17, 25, 29, 37, 41, 49, 61, 65, 77, 85, 89, 97, 109, 121, 125, 137, 145, 149, 161, 169, 181, 197, 205, 209, 217, 221, 229, 257, 265, 277, 281, 301, 305, 317, 329, 337, 349, 361, 365, 385, 389, 397, 401, 425, 449, 457, 461, 469, 481, 485, 505, 517, 529

Offset: 1

Author

Cino Hilliard, May 11 2007, May 17 2007

Keywords

• easy
• nonn

Examples

			For n=7, (7-3)/2 = 2 which is prime so 7 is the first entry.
		

Crossrefs

Cf. A000040.

Programs

Mathematica

Select[Range[550],PrimeQ[(#-3)/2]&]  (* Harvey P. Dale, Feb 09 2011 *)

PARI

g(m) = forprime(p=2,m,n=2*p+3;print1(n","))

Formula

a(n) = 2*prime(n) + 3. - Zak Seidov, May 12 2007