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 A073525 #3 Mar 30 2012 16:49:30 %S A073525 1,2,5,15,51,187,716,2811,11204,45089,182636,743180,3034361,12420945, %T A073525 50946169,209296302,860941813,3545265139,14611979639,60268977054, %U A073525 248744871983,1027188978686,4243751316106,17539851091965,72519657462805,299930389183429,1240806275485094 %N A073525 Result of applying the transformation on generating functions A -> 1/((1-x)*(1-x*A)) to the g.f. for A024718. %C A073525 Equivalently, result of applying same transformation 4 times to g.f. for Catalan numbers A000108. %F A073525 G.f.: -(4*t-1+(-4*t+1)^(1/2))/(6*t^2-5*t+(-4*t+1)^(1/2)*t+1-(-4*t+1)^(1/2)). %Y A073525 Cf. A000108, A014137, A024718. %K A073525 nonn %O A073525 0,2 %A A073525 _N. J. A. Sloane_, Aug 30 2002