A107140 Primes of the form 5x^2 + 7y^2.

5, 7, 73, 83, 157, 257, 383, 433, 523, 563, 587, 647, 727, 853, 857, 887, 1013, 1063, 1097, 1153, 1237, 1567, 1613, 1627, 1697, 1777, 1847, 2063, 2203, 2273, 2393, 2467, 2707, 2803, 2887, 2897, 2917, 3167, 3407, 3433, 3643, 3673, 3727, 3793

Offset

1,1

Comments

Discriminant = -140. 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[5, 0, 7, 10000] (* see A106856 *)

Prog

(PARI) list(lim)=my(v=List(), w, t); for(x=0, sqrtint(lim\5), w=5*x^2; for(y=0, sqrtint((lim-w)\7), if(isprime(t=w+7*y^2), listput(v, t)))); Set(v) \\ Charles R Greathouse IV, Feb 09 2017

Crossrefs

Sequence in context: A109715 A128465 A098967 * A141746 A067198 A340468

Adjacent sequences: A107137 A107138 A107139 * A107141 A107142 A107143

Keyword

nonn,easy

Author

T. D. Noe, May 13 2005

Status

approved