A309726 Numbers k such that k^2 - 12 is prime.

5, 7, 11, 13, 17, 19, 25, 29, 35, 41, 49, 53, 59, 61, 79, 85, 91, 95, 97, 103, 107, 113, 119, 121, 137, 139, 145, 149, 163, 169, 173, 179, 181, 185, 191, 205, 209, 227, 233, 235, 245, 251

Offset: 1

Author

Daniel Starodubtsev, Aug 14 2019

Keywords

• nonn

Comments

All terms are odd and not divisible by 3.

Examples

			11 is in the sequence because 11^2 - 12 = 109, which is prime.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A028870, A028873, A028876, A028879, A028882, A028885, A186815, A090696, A296507.

Cf. A056927.

Programs

Mathematica

Select[Range[5,301,2],PrimeQ[#^2-12]&] (* Harvey P. Dale, Dec 23 2019 *)

PARI

select(n->isprime(n^2-12), [1..1000]) \\ Andrew Howroyd, Aug 14 2019

Formula

If A056927(k) = 12, then k is a term. - A.H.M. Smeets, Aug 15 2019