A139878 Primes of the form 8x^2+8xy+23y^2.

23, 71, 191, 239, 263, 359, 431, 599, 743, 863, 911, 1031, 1103, 1367, 1439, 1583, 1607, 1871, 2039, 2087, 2111, 2207, 2423, 2447, 2543, 2591, 2711, 2879, 2927, 3119, 3623, 3719, 3767, 4127, 4271, 4391, 4463, 4799, 4943, 4967, 5231, 5279

Offset: 1

Author

T. D. Noe, May 02 2008

Keywords

• nonn
• easy

Comments

Discriminant=-672. See A139827 for more information.

Also primes of the forms 23x^2+16xy+32y^2, 15x^2+6xy+23y^2 and 23x^2+4xy+44y^2. See A140633. - T. D. Noe, May 19 2008

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 168 in {23, 71, 95}]; // Vincenzo Librandi, Jul 30 2012

Mathematica

QuadPrimes2[8, -8, 23, 10000] (* see A106856 *)

Formula

The primes are congruent to {23, 71, 95} (mod 168).