A107207 - OEIS

%I #18 Feb 10 2017 15:06:06

%S 7,13,41,59,227,229,271,353,383,461,577,619,643,773,811,839,1021,1307,

%T 1399,1489,1601,1627,1697,1753,1783,1867,1879,2273,2281,2309,2579,

%U 2593,2719,2897,2917,2953,3037,3323,3359,3373,3391,3671,3853,3911

%N Primes of the form 7x^2 + 13y^2.

%C Discriminant = -364. See A107132 for more information.

%H Vincenzo Librandi and Ray Chandler, <a href="/A107207/b107207.txt">Table of n, a(n) for n = 1..10000</a> [First 1000 terms from Vincenzo Librandi]

%H N. J. A. Sloane et al., <a href="https://oeis.org/wiki/Binary_Quadratic_Forms_and_OEIS">Binary Quadratic Forms and OEIS</a> (Index to related sequences, programs, references)

%t QuadPrimes2[7, 0, 13, 10000] (* see A106856 *)

%o (PARI) list(lim)=my(v=List(),w,t); for(x=0, sqrtint(lim\7), w=7*x^2; for(y=0, sqrtint((lim-w)\13), if(isprime(t=w+13*y^2), listput(v,t)))); Set(v) \\ _Charles R Greathouse IV_, Feb 10 2017

%K nonn,easy

%O 1,1

%A _T. D. Noe_, May 13 2005