A232011 Numbers n such that (3n)^2 + 2 is prime.

1, 3, 5, 7, 11, 13, 15, 19, 27, 33, 35, 37, 39, 41, 49, 57, 73, 75, 79, 81, 83, 85, 91, 99, 101, 103, 107, 115, 117, 121, 123, 125, 129, 139, 141, 143, 147, 149, 151, 159, 167, 171, 183, 185, 187, 191, 201, 203, 217, 225, 227, 233, 237, 251, 259, 269, 273, 279

Offset: 1

Author

Jaroslav Krizek, Nov 25 2013

Keywords

• nonn

Comments

Corresponding values of such primes are in A056899(n) for n>2.

Supersequence of A126960 (primes p such that (3p)^2 + 2 is prime).

Examples

			7 is in sequence because (3*7)^2 + 2 = 443 (prime).
		

Links

• Jaroslav Krizek, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000040, A056899, A067201, A126960.

Programs

Mathematica

Select[Range[279], PrimeQ[9 #^2 + 2] &] (* T. D. Noe, Nov 27 2013 *)

PARI

is(n)=isprime(9*n^2+2) \\ Charles R Greathouse IV, Nov 25 2013

Formula

a(n) = sqrt(A056899(n+2) - 2)/3 = A067201(n+2)/3.