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 A124891 #4 Mar 30 2012 18:37:01 %S A124891 1,5,25,137,766,4379,25355,148273,873574,5177450,30833342,184355207, %T A124891 1105977887,6653964847,40131748300,242567280865,1468928473132, %U A124891 8910461020730,54131814523902,329299899410062,2005674943792559 %N A124891 L.g.f.: A(x) = log(G124890(x)) where G124890(x) is the g.f. of A124890. %F A124891 a(n) = A124328(2n+2,n+1) for n>=0; thus a(n) is the number of ordered trees with 2(n+1) edges, with thinning limbs and with root of degree n+1. %e A124891 A(x) = x + 5*x^2/2 + 25*x^3/3 + 137*x^4/4 + 766*x^5/5 + 4379*x^6/6 +... %e A124891 exp(A(x)) = G124890(x) where %e A124891 G124890(x) = 1 + x + 3*x^2 + 11*x^3 + 47*x^4 + 216*x^5 + 1047*x^6 +... %Y A124891 Cf. A124890, A124328, A124889. %K A124891 nonn %O A124891 0,2 %A A124891 _Paul D. Hanna_, Nov 12 2006