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 A115191 #4 Sep 26 2012 04:25:02 %S A115191 1,364,6379,85384,1039873,12146074,139010356,1574773276,17751401206, %T A115191 199685662642,2245313830945,25260355535020,284496154963705, %U A115191 3208676674986850,36246188218732000,410128577783927380 %N A115191 Fifth diagonal (M=5) of triangle A115154 (called Y(3,1)). %F A115191 a(n)= A115154(n+4,n+1), n>=0. %F A115191 Recurrence: a(n)= b(n) - 3*(4*b(n-1)-9*b(n-2)), with b(n):=A064063(n+5), n>=0. %F A115191 G.f.: ((-3+27*x-27*x^2+2*x^4) + 3*(1-3*x)*(1-9*x)*c(3*x))/((2+x)*x^4), with the o.g.f. c(x) of A000108 (Catalan). %e A115191 a(0)= 1 = 1606 - 3*(4*190-9*25); a(1) = 364 = 14506 - 3*(4*1606-9*190). %K A115191 nonn,easy %O A115191 0,2 %A A115191 _Wolfdieter Lang_, Feb 23 2006