This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A139644 #21 Sep 08 2022 08:45:33
%S A139644 109,421,541,709,1009,1129,1201,1381,1429,1549,1621,1789,1801,2221,
%T A139644 2269,2389,2521,2689,3049,3061,3109,3229,3301,3361,3469,3529,3889,
%U A139644 4201,4561,4621,4729,4789,4909,5209,5569,5581,5749,5821,5881,6301
%N A139644 Primes of the form x^2 + 105*y^2.
%C A139644 Discriminant=-420. See A139643 for more information.
%C A139644 The primes are congruent to {1, 109, 121, 169, 289, 361} (mod 420).
%H A139644 Vincenzo Librandi and Ray Chandler, <a href="/A139644/b139644.txt">Table of n, a(n) for n = 1..10000</a> (first 1000 terms from Vincenzo Librandi).
%H A139644 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 A139644 QuadPrimes2[1, 0, 105, 10000] (* see A106856 *)
%o A139644 (Magma) [ p: p in PrimesUpTo(7000) | p mod 420 in {1, 109, 121, 169, 289, 361}]; // _Vincenzo Librandi_, Jul 28 2012
%o A139644 (Magma) k:=105; [p: p in PrimesUpTo(7000) | NormEquation(k, p) eq true]; // _Bruno Berselli_, Jun 01 2016
%K A139644 nonn,easy
%O A139644 1,1
%A A139644 _T. D. Noe_, Apr 29 2008