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 A060912 #3 May 10 2013 12:44:45
%S A060912 1,1,4,25,218,2451,33112,516727,9117180,179330905,3890434256,
%T A060912 92271385449,2374775505016,65900749176835,1961009596461840,
%U A060912 62275489622799751,2101798757669917328,75111617959762807473
%N A060912 E.g.f.: exp(x*exp(x*exp(x*exp(x*exp(x)))) + 1/2*x^2*exp(x*exp(x*exp(x*exp(x))))^2).
%D A060912 I. P. Goulden and D. M. Jackson, Combinatorial Enumeration, Wiley, N.Y., 1983.
%F A060912 E.g.f.: exp(Sum_{d|m} T_k^d/d), where T_k = x*exp(T_(k - 1)), k >= 1, T_0 = x; k = 4, m = 2.
%Y A060912 Cf. A000949 - A000951, A060905 - A060913.
%K A060912 nonn
%O A060912 0,3
%A A060912 _Vladeta Jovovic_, Apr 07 2001