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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

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OFFSET

1,1

LINKS

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

EXAMPLE

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

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 *)