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 A156131 #7 Sep 29 2013 04:23:09 %S A156131 1,3,19,177,2201,34203,637819,13876377,345022001,9650948403, %T A156131 299951259619,10254726248577,382459993625801,15452902408998603, %U A156131 672386203441625419,31346622138810396777,1558803698602736533601,82360892667114765064803,4607594447779876771255219 %N A156131 Q_n(3) (see A104035). %F A156131 G.f.: 1/Q(0), where Q(k) = 1 - 3*x*(2*k+1) - 10*x^2*(k+1)^2/Q(k+1); (continued fraction). - _Sergei N. Gladkovskii_, Sep 28 2013 %K A156131 nonn %O A156131 0,2 %A A156131 _N. J. A. Sloane_, Nov 06 2009