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 A124558 #3 Mar 30 2012 18:37:01
%S A124558 1,2,15,204,4345,133212,5621371,319211576,24097683942,2399637270890,
%T A124558 313606810455697,53638534570897308,11984755429488415041,
%U A124558 3491974842611221434342,1324861497596788043284935
%N A124558 Secondary diagonal of table A124550; a(n) = A124550(n+1,n).
%C A124558 In table A124550, the g.f. of row n, R_n(y), simultaneously satisfies: R_n(y) = [ Sum_{k>=0} y^k * R_{n*k}(y) ]^n for n>=0.
%F A124558 a(n) is divisible by (n+1): A124559(n) = a(n)/(n+1).
%Y A124558 Cf. A124550 (table); A124557, A124559; A124551, A124552, A124554, A124555, A124556.
%K A124558 nonn
%O A124558 0,2
%A A124558 _Paul D. Hanna_, Nov 07 2006