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 A033215 #27 Jul 08 2025 19:44:40
%S A033215 37,109,193,277,337,373,421,457,541,613,673,709,757,877,1009,1033,
%T A033215 1093,1117,1129,1201,1213,1297,1381,1429,1453,1549,1597,1621,1789,
%U A033215 1801,1873,1933,2017,2053,2137,2221
%N A033215 Primes of form x^2+21*y^2.
%D A033215 David A. Cox, "Primes of the Form x^2 + n y^2", Wiley, 1989.
%H A033215 Vincenzo Librandi and Ray Chandler, <a href="/A033215/b033215.txt">Table of n, a(n) for n = 1..10000</a> [First 1000 terms from Vincenzo Librandi]
%H A033215 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 A033215 Equivalently, primes congruent to {1, 25, or 37} (mod 84). - _T. D. Noe_, Apr 29 2008 [See e.g. Cox, p. 36. - _N. J. A. Sloane_, May 27 2014]
%t A033215 QuadPrimes2[1, 0, 21, 10000] (* see A106856 *)
%Y A033215 Cf. A139643.
%K A033215 nonn,easy
%O A033215 1,1
%A A033215 _N. J. A. Sloane_