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Primes of the form 2x^2 + 23y^2.
2

%I #18 Feb 09 2017 15:01:39

%S 2,23,31,41,73,151,223,239,257,311,449,577,593,599,601,607,647,673,

%T 719,823,863,929,967,991,1087,1129,1153,1223,1289,1297,1327,1481,1543,

%U 1559,1823,1871,1889,1913,2063,2129,2143,2377,2441,2473,2657,2663

%N Primes of the form 2x^2 + 23y^2.

%C Discriminant = -184. See A107132 for more information.

%H Vincenzo Librandi and Ray Chandler, <a href="/A107153/b107153.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[2, 0, 23, 10000] (* see A106856 *)

%o (PARI) list(lim)=my(v=List(),w,t); for(x=0, sqrtint(lim\2), w=2*x^2; for(y=0, sqrtint((lim-w)\23), if(isprime(t=w+23*y^2), listput(v,t)))); Set(v) \\ _Charles R Greathouse IV_, Feb 09 2017

%K nonn,easy

%O 1,1

%A _T. D. Noe_, May 13 2005