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E.g.f.: exp(x*exp(x*exp(x*exp(x))) + 1/2*x^2*exp(x*exp(x*exp(x)))^2).
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%I #3 May 10 2013 12:44:45

%S 1,1,4,25,218,2331,29152,417607,6746700,121312441,2401341056,

%T 51857779689,1212621122176,30509979042115,821524617293304,

%U 23563369209520711,717014609781379568,23064363484845390513

%N E.g.f.: exp(x*exp(x*exp(x*exp(x))) + 1/2*x^2*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 = 3, m = 2.

%Y Cf. A000949 - A000951, A060905 - A060913.

%K nonn

%O 0,3

%A _Vladeta Jovovic_, Apr 07 2001