|
%I #19 Feb 09 2017 13:02:34
%S 5,41,61,109,149,241,269,281,389,409,421,449,569,601,641,661,701,821,
%T 829,881,929,1069,1129,1181,1201,1301,1321,1381,1429,1481,1489,1609,
%U 1801,1889,1901,1949,2129,2141,2161,2221,2269,2281,2309,2341,2381
%N Primes of the form 4x^2 + 5y^2.
%C Discriminant = -80.
%H Vincenzo Librandi and Ray Chandler, <a href="/A106963/b106963.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[4, 0, 5, 10000] (* see A106856 *)
%o (PARI) list(lim)=my(v=List(),w,t); for(x=0, sqrtint(lim\4), w=4*x^2; for(y=1, sqrtint((lim-w)\5), if(isprime(t=w+5*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 09 2005
|
