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%I #3 May 10 2013 12:44:45
%S 1,1,4,25,218,2451,33112,516727,9117180,179330905,3890434256,
%T 92271385449,2374775505016,65900749176835,1961009596461840,
%U 62275489622799751,2101798757669917328,75111617959762807473
%N 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 I. P. Goulden and D. M. Jackson, Combinatorial Enumeration, Wiley, N.Y., 1983.
%F 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 Cf. A000949 - A000951, A060905 - A060913.
%K nonn
%O 0,3
%A _Vladeta Jovovic_, Apr 07 2001