A201477 Primes of the form 3n^2 + 4.

7, 31, 79, 151, 367, 1087, 1327, 1879, 2887, 3271, 4111, 4567, 6079, 7207, 8431, 15991, 16879, 17791, 19687, 23767, 24847, 25951, 34351, 39679, 42487, 49927, 51487, 54679, 56311, 63079, 73951, 102679, 104911, 111751, 123631, 126079, 128551

Offset: 1

Author

Vincenzo Librandi, Dec 02 2011

Keywords

• nonn
• easy

Comments

Equivalently, generalized cuban primes of the form (x^3-y^3)/(x-y) with x=y+4 (cf. A002407, A007645). - N. J. A. Sloane, Jan 29 2013

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..5000

Crossrefs

Cf. A002407. A subsequence of A007645. - N. J. A. Sloane, Jan 29 2013

Cf. A111052 (corresponding values of n). - Zak Seidov, Feb 04 2016

Programs

Magma

[a: n in [0..400] | IsPrime(a) where a is 3*n^2+4];

Mathematica

Select[Table[3n^2+4,{n,0,700}],PrimeQ]

PARI

lista(nn) = {for (n=0, nn, if (isprime(p=3*n^2 + 4), print1(p, ", ")););} \\ Michel Marcus, Feb 04 2016

Formula

a(n) = 4 + 3*A111052(n)^2. - Zak Seidov, Feb 04 2016