A107134 Primes of the form x^2+28y^2.

29, 37, 53, 109, 113, 137, 149, 193, 197, 233, 277, 281, 317, 337, 373, 389, 401, 421, 449, 457, 541, 557, 569, 613, 617, 641, 653, 673, 701, 709, 757, 809, 821, 877, 953, 977, 1009, 1033, 1061, 1093, 1117, 1129, 1201, 1213, 1229, 1289, 1297, 1373, 1381

Offset: 1

Author

T. D. Noe, May 13 2005

Keywords

• nonn
• easy

Comments

Discriminant=-112. See A107132 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)

Crossrefs

Cf. A139643.

Programs

Magma

[ p: p in PrimesUpTo(2000) | p mod 28 in {1, 9, 25} ]; // Vincenzo Librandi, Jul 23 2012

Mathematica

QuadPrimes2[1, 0, 28, 10000] (* see A106856 *)

Formula

The primes are congruent to {1, 9, 25} (mod 28). - T. D. Noe, Apr 29 2008