A107170 Primes of the form 2x^2 + 31y^2.

2, 31, 103, 193, 281, 311, 479, 521, 617, 857, 937, 1063, 1423, 1489, 1657, 1831, 1847, 2543, 2591, 2609, 2671, 2711, 2729, 2753, 2903, 2953, 3023, 3089, 3167, 3319, 3559, 3697, 3761, 3769, 3823, 3863, 4079, 4111, 4201, 4561, 4639, 4903

Offset

1,1

Comments

Discriminant = -248. 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)

Mathematica

QuadPrimes2[2, 0, 31, 10000] (* see A106856 *)

Prog

(PARI) list(lim)=my(v=List(), w, t); for(x=0, sqrtint(lim\2), w=2*x^2; for(y=0, sqrtint((lim-w)\31), if(isprime(t=w+31*y^2), listput(v, t)))); Set(v) \\ Charles R Greathouse IV, Feb 10 2017

Crossrefs

Sequence in context: A101254 A243472 A336788 * A273403 A291052 A267888

Adjacent sequences: A107167 A107168 A107169 * A107171 A107172 A107173

Keyword

nonn,easy

Author

T. D. Noe, May 13 2005

Status

approved