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 A116871 #2 Mar 31 2012 13:20:11 %S A116871 42,174,645,2333,8398,30275,109550,398180,1453908,5332407,19639521, %T A116871 72616727,269473750,1003347975,3747412770,14036374680,52714429260, %U A116871 198459284400,748867149234,2831788492218,10729442739596 %N A116871 Sixth column of triangle A067323. %C A116871 Also sixth diagonal sequence of triangle A028364. %F A116871 a(n)= A067323(n+5,5), n>=0. %F A116871 a(n)= A028364(5+n,n) = sum(C(k)*C(5+n-k),k=0..n), n>=0, with the Catalan numbers C(n):=A000108(n). %F A116871 G.f.: (c(x)^3)sum(C(4, k)*c(x)^k, k=0..4), with C(n, m) := (m+1)*binomial(2*n-m, n-m)/(n+1) (Catalan convolutions A033184). %Y A116871 Cf. A067326 (fifth column of A067323). %K A116871 nonn,easy %O A116871 0,1 %A A116871 _Wolfdieter Lang_, Mar 24 2006