A139663 - OEIS

%I #20 Sep 08 2022 08:45:33

%S 521,569,601,641,809,881,1049,1249,1361,1481,1609,1889,2081,2089,2129,

%T 2161,2441,2521,2609,2729,3041,3121,3169,3329,3449,3761,3769,3929,

%U 4001,4241,4289,4481,4729,4801,4889,4969,5009,5209,5281,5521,5641

%N Primes of the form x^2 + 520*y^2.

%C Discriminant = -2080. See A139643 for more information.

%C The primes are congruent to {1, 9, 49, 81, 121, 129, 209, 289, 321, 329, 361, 441} (mod 520).

%H Vincenzo Librandi and Ray Chandler, <a href="/A139663/b139663.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, 520, 10000] (* see A106856 *)

%o (Magma) [ p: p in PrimesUpTo(7000) | p mod 520 in {1, 9, 49, 81, 121, 129, 209, 289, 321, 329, 361, 441}]; // _Vincenzo Librandi_, Jul 29 2012

%o (Magma) k:=520; [p: p in PrimesUpTo(6000) | NormEquation(k, p) eq true]; // _Bruno Berselli_, Jun 01 2016

%K nonn,easy

%O 1,1

%A _T. D. Noe_, Apr 29 2008