A253142 Numbers k such that k + 15 and k^2 + 15 are prime.

2, 4, 8, 14, 16, 22, 26, 32, 38, 44, 46, 52, 64, 68, 86, 88, 98, 124, 134, 158, 178, 184, 196, 212, 236, 242, 248, 256, 262, 296, 298, 316, 322, 338, 364, 374, 386, 394, 452, 472, 484, 488, 548, 578, 586, 598, 602, 626, 632, 638, 646, 658, 662, 676, 694, 718, 728, 736, 794, 806, 842, 848, 862

Offset: 1

Author

Zak Seidov, Dec 27 2014

Keywords

• nonn
• changed

Examples

			2 + 15 = 17 and 2^2 + 15 = 19 are both prime, so 2 is in the sequence.
		

Links

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

Crossrefs

Intersection of A086303 and A121982.

Programs

Maple

select(t -> isprime(t+15) and isprime(t^2+15), [seq(i,i=2..1000,2)]); # Robert Israel, May 07 2019

Mathematica

p = 15; Select[Range[2,1000,2], PrimeQ[p + #^2] && PrimeQ[p + #] &]
Select[Range[2,1000,2],AllTrue[{#,#^2}+15,PrimeQ]&] (* Harvey P. Dale, Jun 08 2023 *)