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 A243186 #10 Jun 03 2022 14:56:00
%S A243186 0,1,2,4,8,9,11,16,18,22,25,32,35,36,43,44,49,50,64,65,67,70,72,81,86,
%T A243186 88,91,98,99,100,107,113,121,128,130,134,137,140,144,155,162,163,169,
%U A243186 172,176,179,182,193,196,198,200
%N A243186 Nonnegative integers of the form x^2 + 6xy - 5y^2.
%C A243186 Discriminant 56.
%C A243186 Nonnegative integers of the form 2x^2 - 7y^2. - _Jon E. Schoenfield_, Jun 03 2022
%H A243186 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 A243186 Reap[For[n = 0, n <= 200, n++, If[Reduce[1*x^2 + 6*x*y - 5*y^2 == n, {x, y}, Integers] =!= False, Sow[n]]]][[2, 1]]
%Y A243186 Primes: A141190.
%K A243186 nonn
%O A243186 1,3
%A A243186 _N. J. A. Sloane_, Jun 05 2014