A139920 Primes of the form 19x^2+18xy+19y^2.

19, 59, 131, 139, 251, 419, 619, 691, 811, 859, 971, 1091, 1259, 1291, 1459, 1531, 1571, 1699, 1811, 1931, 1979, 2099, 2131, 2371, 2411, 2539, 2579, 2659, 2819, 2939, 2971, 3251, 3331, 3491, 3499, 3659, 3779, 4051, 4091, 4219, 4259, 4339

Offset: 1

Author

T. D. Noe, May 02 2008

Keywords

• nonn
• easy

Comments

Discriminant=-1120. See A139827 for more information.

Links

• Vincenzo Librandi and Ray Chandler, Table of n, a(n) for n = 1..10000 [First 1000 terms from Vincenzo Librandi]
• N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)

Programs

Magma

[ p: p in PrimesUpTo(6000) | p mod 280 in [19, 59, 131, 139, 171, 251]]; // Vincenzo Librandi, Aug 01 2012

Mathematica

Union[QuadPrimes2[19, 18, 19, 10000], QuadPrimes2[19, -18, 19, 10000]] (* see A106856 *)

Formula

The primes are congruent to {19, 59, 131, 139, 171, 251} (mod 280).