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 A243188 #20 Jul 14 2019 17:24:51
%S A243188 0,1,4,9,10,16,21,25,34,36,40,49,61,64,66,81,84,85,90,100,106,109,121,
%T A243188 129,136,144,154,160,165,169,181,189,196,201,210,225,226,229,241,244,
%U A243188 250,256,264,265,274,289,301,306,309,324,336,340,346,349,354,360
%N A243188 Nonnegative numbers of the form x^2 + 6*x*y - 6*y^2.
%C A243188 Discriminant 60.
%C A243188 Also numbers representable as x^2 + 8*x*y + y^2 with 0 <= x <= y. - _Gheorghe Coserea_, Jul 29 2018
%C A243188 Also numbers of the form x^2 - 15*y^2. - _Jianing Song_, Jul 31 2018
%H A243188 Gheorghe Coserea, <a href="/A243188/b243188.txt">Table of n, a(n) for n = 1..100001</a>
%H A243188 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 A243188 Reap[For[n = 0, n <= 200, n++, If[Reduce[ 1*x^2 + 6*x*y - 6*y^2 == n, {x, y}, Integers] =!= False, Sow[n]]]][[2, 1]]
%Y A243188 Cf. A031363.
%Y A243188 Primes: A107152.
%K A243188 nonn
%O A243188 1,3
%A A243188 _N. J. A. Sloane_, Jun 05 2014
%E A243188 More terms from _Colin Barker_, Apr 07 2015