A176557 Primes of the form 7*x^2 - 5*y^2, where x and y are successive natural numbers.

7, 23, 43, 67, 127, 163, 347, 463, 743, 823, 907, 1087, 1283, 1607, 1723, 2503, 2647, 3767, 3943, 5923, 6143, 6367, 6827, 7547, 8563, 9643, 9923, 11083, 11383, 13267, 14947, 15647, 16363, 17467, 18223, 19387, 20183, 21407, 24847, 25747, 26203

Offset: 1

Author

Giovanni Teofilatto, Apr 20 2010

Keywords

• nonn

Comments

a(n) is congruent 3 mod 4.

Primes of the form 2x^2+10x-5, x>=1. [From R. J. Mathar and Vincenzo Librandi, Apr 21 2010]

Crossrefs

Cf. A176470

Extensions

More terms from R. J. Mathar and Vincenzo Librandi, Apr 21 2010