A145490 Numbers k such that 6k+19 is prime and absolute value of 12k+1 is also prime.

-2, -1, 3, 8, 9, 13, 15, 20, 23, 29, 34, 35, 48, 55, 59, 63, 69, 73, 78, 84, 93, 100, 104, 115, 119, 134, 135, 139, 148, 150, 169, 174, 178, 185, 189, 199, 203, 210, 213, 218, 238, 254, 255, 260, 265, 268, 275, 280, 288, 289, 293, 294, 295, 308, 309, 335, 344

Offset: 1

Author

Artur Jasinski, Oct 11 2008

Keywords

• sign
• easy

Links

• Nathaniel Johnston, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A063908-A063913, A092109, A145471-A145490.

Programs

Maple

with(numtheory): a:=proc(n) if(isprime(6*n+19) and isprime(abs(12*n+1)))then return n: fi: return NULL: end: seq(a(n),n=-2..350); # Nathaniel Johnston, Jul 26 2011

Formula

a(n) = (A145480(n-2)-1)/12 for n >= 3.

Extensions

Corrected by Arkadiusz Wesolowski, Jul 26 2011