A139975 Primes of the form 20x^2+20xy+31y^2.

31, 71, 151, 239, 271, 359, 431, 479, 631, 839, 1151, 1279, 1319, 1399, 1471, 1831, 1879, 2039, 2111, 2351, 2399, 2671, 2711, 2719, 2879, 3079, 3191, 3271, 3359, 3391, 3671, 3911, 3919, 4231, 4271, 4519, 4591, 4639, 4751, 4799, 4831, 4919

Offset

1,1

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)

Formula

The primes are congruent to {31, 71, 111, 119, 151, 239, 271, 279, 319, 359, 431, 479} (mod 520).

Mathematica

QuadPrimes2[20, -20, 31, 10000] (* see A106856 *)

Prog

(Magma) [p: p in PrimesUpTo(6000) | p mod 520 in [31, 71, 111, 119, 151, 239, 271, 279, 319, 359, 431, 479]]; // Vincenzo Librandi, Aug 03 2012

Crossrefs

Sequence in context: A142195 A237992 A356457 * A050957 A331260 A127345

Adjacent sequences: A139972 A139973 A139974 * A139976 A139977 A139978

Keyword

nonn,easy

Author

T. D. Noe, May 02 2008

Extensions

Corrected and extended b-file - Ray Chandler, Aug 01 2014

Status

approved