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 A139948 #17 Sep 08 2022 08:45:34
%S A139948 19,103,223,271,307,523,727,859,1039,1063,1123,1279,1291,1447,1483,
%T A139948 1531,1543,1699,1783,1879,1951,1987,2287,2371,2467,2551,2707,2719,
%U A139948 2803,2971,3079,3163,3307,3331,3391,3583,3727,3919,4003,4231,4339
%N A139948 Primes of the form 19x^2+4xy+19y^2.
%C A139948 Discriminant=-1428. See A139827 for more information.
%H A139948 Vincenzo Librandi and Ray Chandler, <a href="/A139948/b139948.txt">Table of n, a(n) for n = 1..10000</a> [First 1000 terms from Vincenzo Librandi]
%H A139948 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 A139948 The primes are congruent to {19, 55, 103, 115, 223, 271, 307, 355, 451, 475, 523, 535, 559, 727, 859, 871, 943, 1039, 1063, 1123, 1147, 1279, 1291, 1375} (mod 1428).
%t A139948 Union[QuadPrimes2[19, 4, 19, 10000], QuadPrimes2[19, -4, 19, 10000]] (* see A106856 *)
%o A139948 (Magma) [ p: p in PrimesUpTo(6000) | p mod 1428 in [19, 55, 103, 115, 223, 271, 307, 355, 451, 475, 523, 535, 559, 727, 859, 871, 943, 1039, 1063, 1123, 1147, 1279, 1291, 1375]];// _Vincenzo Librandi_, Aug 02 2012
%K A139948 nonn,easy
%O A139948 1,1
%A A139948 _T. D. Noe_, May 02 2008