A139666 Primes of the form x^2 + 1320*y^2.

1321, 1489, 1609, 2161, 2281, 2689, 3001, 3169, 3529, 4129, 4801, 5281, 5449, 5569, 5641, 6121, 6361, 6961, 7129, 7489, 7561, 7681, 8089, 8209, 8761, 9001, 9241, 9601, 9769, 10321, 10729, 12049, 12241, 12409, 12721, 12841, 13249, 13729

Offset: 1

Author

T. D. Noe, Apr 29 2008

Keywords

• nonn
• easy

Comments

Discriminant = -5280. See A139643 for more information.

The primes are congruent to {1, 49, 169, 289, 361, 529, 841, 889, 961, 1081} (mod 1320).

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(15000) | p mod 1320 in {1, 49, 169, 289, 361, 529, 841, 889, 961, 1081}]; // Vincenzo Librandi, Jul 29 2012

Magma

k:=1320; [p: p in PrimesUpTo(14000) | NormEquation(k, p) eq true]; // Bruno Berselli, Jun 01 2016

Mathematica

QuadPrimes2[1, 0, 1320, 10000] (* see A106856 *)