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 A115188 #2 Oct 12 2012 14:40:25 %S A115188 1,13,115,1036,9688,93571,927523,9387580,96634294,1008719002, %T A115188 10653244294,113630599852,1222361061310,13246563382735, %U A115188 144479425979635,1584810988780420,17471975574010630,193493968384827670 %N A115188 Second diagonal (M=2) of triangle A115154 (called Y(3,1)). %F A115188 a(n)= A115154(n+1,n+1), n>=0. %F A115188 Recurrence: a(n)= b(n) - 3*b(n-1), with b(n):= A064063(n+2), n>=0. %F A115188 G.f.: ((-3+2*x) + 3*(1-3*x)*c(3*x))/(x*(2+x)), with the o.g.f. c(x) of A000108 (Catalan). %e A115188 115 = a(2) = A064063(4) - 3* A064063(3) = 190 - 3*25. %K A115188 nonn,easy %O A115188 0,2 %A A115188 _Wolfdieter Lang_, Feb 23 2006