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 A230108 #14 Jun 22 2019 12:48:31
%S A230108 2,3,6,8,11,12,18,19,22,24,27,32,38,43,44,48,50,51,54,59,66,67,72,75,
%T A230108 76,83,86,88,96,98,99,102,107,108,114,118,123,128,131,134,139,146,147,
%U A230108 150,152,162,163,166,171,172,176,178,179
%N A230108 Values of d such that the equation x^2 - d*y^2 = 2*d has integer solutions.
%e A230108 43 appears in the sequence because the equation x^2 - 43*y^2 = 86 has integer solutions, such as (x,y) = (387,59).
%t A230108 Select[Range[200],FindInstance[x^2-#*y^2==2*#,{x,y},Integers]!={}&] (* _Harvey P. Dale_, Jun 22 2019 *)
%o A230108 (PARI) is(n)=sol=bnfisintnorm(bnfinit(z^2-n),2*n);if(!#sol,0,p=polcoeff(sol[1],0);p==floor(p)) \\ _Ralf Stephan_, Oct 19 2013
%Y A230108 Cf. A172000, A230109.
%K A230108 nonn
%O A230108 1,1
%A A230108 _Colin Barker_, Oct 09 2013