A139984 Primes of the form 3x^2+280y^2.

3, 283, 307, 523, 643, 787, 1123, 1483, 1627, 1867, 1987, 2203, 2467, 2707, 2803, 3163, 3307, 3547, 3643, 4003, 4483, 4507, 4723, 4987, 5227, 5323, 5347, 5563, 5683, 5827, 6067, 6163, 6907, 7027, 7243, 7507, 7867, 8707, 8923, 9043, 9187

Offset: 1

Author

T. D. Noe, May 02 2008

Keywords

• nonn
• easy

Comments

Discriminant=-3360. 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

[3] cat [p: p in PrimesUpTo(10000) | p mod 840 in [187, 283, 307, 523, 643, 787]]; // Vincenzo Librandi, Aug 03 2012

Mathematica

QuadPrimes2[3, 0, 280, 10000] (* see A106856 *)

Formula

Except for 3, the primes are congruent to {187, 283, 307, 523, 643, 787} (mod 840).