A308269 Primes p such that 2*p^2 + 2*p - 9 is prime.

2, 7, 19, 37, 67, 109, 127, 157, 229, 349, 397, 457, 619, 727, 829, 877, 1117, 1129, 1237, 1249, 1279, 1327, 1447, 1459, 1489, 1699, 1777, 1789, 1867, 1879, 1987, 1999, 2179, 2269, 2377, 2389, 2467, 2539, 2647, 2659, 2767, 2857, 2917, 3019, 3109, 3169, 3187, 3217, 3229, 3307, 3319, 3457, 3637

Offset

1,1

Comments

Primes p such that 4*p^2 is in A308268.

Other than 2, all terms == 1 (mod 6).

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

a(3) = 19 is in the sequence because 19 and 2*19^2 + 2*19 - 9 = 751 are prime.

Maple

select(p -> isprime(p) and isprime(2*p^2 + 2*p - 9), [2, seq(i, i=7..1000, 6)]);

Mathematica

Select[Prime[Range[600]], PrimeQ[2#^2+2#-9]&] (* Harvey P. Dale, Jun 14 2021 *)

Prog

(Magma) [p:p in PrimesUpTo(5000)|IsPrime(2*p^2 + 2*p - 9)]; Marius A. Burtea, May 17 2019

Crossrefs

Cf. A308268.

Sequence in context: A213892 A152608 A334520 * A038562 A140610 A152461

Adjacent sequences: A308266 A308267 A308268 * A308270 A308271 A308272

Keyword

nonn

Author

Robert Israel, May 17 2019

Status

approved