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%I #23 Aug 05 2014 14:16:29
%S 19,31,79,109,151,181,199,211,229,271,331,349,409,421,439,499,571,601,
%T 619,631,661,691,709,769,811,829,859,919,991,1021,1039,1051,1069,1129,
%U 1171,1201,1249,1291,1321,1381,1399,1429,1459,1471,1489,1531,1579
%N Primes of the form x^2+xy+4y^2, with x and y nonnegative.
%C Discriminant=-15.
%C Subset of A033212. - _Robert Israel_, Jul 25 2014
%H Vincenzo Librandi and Rick L. Shepherd, <a href="/A106861/b106861.txt">Table of n, a(n) for n = 1..10000</a> (first 2000 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)
%p N:= 1000; # to get all terms <= N
%p Primes:= select(isprime,[seq(2*n+1,n=1..floor((N-1)/2))]):
%p filter:= proc(p) local S;
%p S:= remove(hastype,[isolve(x^2+x*y+4*y^2=p)],negint);
%p nops(S) > 0
%p end proc:
%p A:= select(filter,Primes); # _Robert Israel_, Jul 25 2014
%t QuadPrimes2[1, 1, 4, 1000000] (* see A106856 *)
%Y Cf. A033212.
%K nonn,easy
%O 1,1
%A _T. D. Noe_, May 09 2005