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 A139993 #16 Sep 08 2022 08:45:34
%S A139993 61,181,229,349,661,829,1021,1069,1669,1741,1861,2029,2341,2749,3181,
%T A139993 3541,3709,4021,4261,4549,4861,5101,5701,5869,6229,6709,6781,6949,
%U A139993 7069,7549,7621,7741,7789,8221,8389,8461,8581,8629,9421,9901,10069
%N A139993 Primes of the form 21x^2+40y^2.
%C A139993 Discriminant=-3360. See A139827 for more information.
%C A139993 Also primes of the form 45x^2+30xy+61y^2. See A140633. - _T. D. Noe_, May 19 2008
%H A139993 Vincenzo Librandi and Ray Chandler, <a href="/A139993/b139993.txt">Table of n, a(n) for n = 1..10000</a> [First 1000 terms from Vincenzo Librandi]
%H A139993 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 A139993 The primes are congruent to {61, 181, 229, 349, 661, 829} (mod 840).
%t A139993 QuadPrimes2[21, 0, 40, 10000] (* see A106856 *)
%o A139993 (Magma) [p: p in PrimesUpTo(12000) | p mod 840 in [61, 181, 229, 349, 661, 829]]; // _Vincenzo Librandi_, Aug 03 2012
%K A139993 nonn,easy
%O A139993 1,1
%A A139993 _T. D. Noe_, May 02 2008