A139976 Primes of the form 23x^2+6xy+23y^2.

23, 103, 127, 263, 367, 503, 607, 647, 727, 823, 887, 1063, 1223, 1303, 1327, 1447, 1543, 1583, 1663, 1823, 1847, 2063, 2207, 2287, 2383, 2447, 2687, 2887, 2903, 3407, 3527, 3623, 3727, 3767, 3823, 3847, 3943, 4007, 4423, 4447, 4463, 4567

Offset: 1

Author

T. D. Noe, May 02 2008

Keywords

• nonn
• easy

Comments

Discriminant=-2080. 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 520 in [23, 87, 103, 127, 183, 207, 263, 287, 303, 367, 407, 503]]; // Vincenzo Librandi, Aug 03 2012

Mathematica

Union[QuadPrimes2[23, 6, 23, 10000], QuadPrimes2[23, -6, 23, 10000]] (* see A106856 *)

Formula

The primes are congruent to {23, 87, 103, 127, 183, 207, 263, 287, 303, 367, 407, 503} (mod 520).