A139655 - OEIS

%I #22 Sep 08 2022 08:45:33

%S 281,401,449,569,641,809,1009,1129,1201,1289,1409,1481,1801,2081,2129,

%T 2521,2689,2801,2969,3049,3089,3329,3361,3529,3761,3889,3929,4001,

%U 4201,4481,4561,4649,4729,5009,5209,5441,5569,5849,5881,6329,6449

%N Primes of the form x^2 + 280*y^2.

%C Discriminant=-1120. See A139643 for more information.

%C The primes are congruent to {1, 9, 81, 121, 169, 249} (mod 280).

%H Vincenzo Librandi and Ray Chandler, <a href="/A139655/b139655.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[1, 0, 280, 10000] (* see A106856 *)

%o (Magma) [ p: p in PrimesUpTo(7000) | p mod 280 in {1, 9, 81, 121, 169, 249}]; // _Vincenzo Librandi_, Jul 29 2012

%o (Magma) k:=280; [p: p in PrimesUpTo(7000) | NormEquation(k, p) eq true]; // _Bruno Berselli_, Jun 01 2016

%K nonn,easy

%O 1,1

%A _T. D. Noe_, Apr 29 2008