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%I #19 Sep 08 2022 08:45:33
%S 19,31,139,199,271,439,619,691,811,859,1039,1231,1279,1291,1399,1459,
%T 1531,1699,1879,1951,2131,2239,2371,2539,2551,2659,2719,2791,2971,
%U 3079,3331,3391,3499,3559,3631,3919,4051,4219,4231,4339,4591,4639
%N Primes of the form 6x^2 + 6xy + 19y^2.
%C Discriminant = -420. See A139827 for more information.
%C Also primes of the forms 19x^2 + 12xy + 24y^2 and 19x^2 + 16xy + 31y^2. See A140633. - _T. D. Noe_, May 19 2008
%H Vincenzo Librandi and Ray Chandler, <a href="/A139847/b139847.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)
%F The primes are congruent to {19, 31, 139, 199, 271, 391} (mod 420).
%t QuadPrimes2[6, -6, 19, 10000] (* see A106856 *)
%o (Magma) [ p: p in PrimesUpTo(6000) | p mod 420 in {19, 31, 139, 199, 271, 391}]; // _Vincenzo Librandi_, Jul 29 2012
%o (PARI) list(lim)=my(v=List(), s=[19, 31, 139, 199, 271, 391]); forprime(p=19, lim, if(setsearch(s, p%420), listput(v, p))); Vec(v) \\ _Charles R Greathouse IV_, Feb 10 2017
%K nonn,easy
%O 1,1
%A _T. D. Noe_, May 02 2008
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