A174152 Primes p such that p^2+p+9 is also prime.

13, 19, 43, 79, 139, 151, 211, 271, 373, 433, 523, 643, 739, 751, 769, 853, 919, 1033, 1051, 1093, 1129, 1171, 1423, 1429, 1471, 1531, 1579, 1663, 1741, 1759, 1789, 1933, 2053, 2281, 2389, 2521, 2689, 2731, 2749, 2833, 3061, 3109, 3163, 3271, 3313, 3319

Offset: 1

Author

Vincenzo Librandi, Mar 10 2010

Keywords

• nonn
• easy

Examples

			For p=13, 13^2+13+9=191; p=19, 19^2+19+9=389; p=43, 43^2+43+9=1901.
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000040, A027757.

Subsequence of A002476.

Programs

Magma

[p: p in PrimesUpTo(10000) | IsPrime(p^2+p+9)];

Mathematica

Select[Prime[Range[500]], PrimeQ[#^2 + # + 9]&] (* Vincenzo Librandi, Apr 16 2013 *)

Formula

A027757 INTERSECT A000040. [From R. J. Mathar, Jul 06 2010]