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%I #12 Apr 03 2015 19:27:11
%S 1,1,1,3,7,21,63,203,655,2225,7519,26279,91601,326873,1162873,4215645,
%T 15229413,55842223,204204265,755626769,2788876167,10398436275,
%U 38671589327,145061791275,542955212801,2047149292105,7702710310237
%N Number of dissimilar forests on n nodes.
%H T. D. Noe, <a href="/A121797/b121797.txt">Table of n, a(n) for n=0..200</a>
%H Philippe Flajolet, Éric Fusy, Xavier Gourdon, Daniel Panario and Nicolas Pouyanne, <a href="http://arxiv.org/abs/math.CO/0606370">A Hybrid of Darboux's Method and Singularity Analysis in Combinatorial Asymptotics</a>, arXiv:math.CO/0606370
%F G.f.: Product_{n=1..infinity} (1+T_n x^n), where T_n (A000108) has g.f. (1-sqrt(1-4x))/2. - _T. D. Noe_, Oct 08 2006
%t nn=200; t=Rest[CoefficientList[Series[1-Sqrt[1-4x]/2, {x,0,nn}],x]]; CoefficientList[Series[Product[(1+t[[k]]*x^k), {k,nn}], {x,0,nn}],x] (* _T. D. Noe_, Oct 08 2006 *)
%K nonn
%O 0,4
%A _N. J. A. Sloane_, Oct 08 2006
%E More terms from _T. D. Noe_, Oct 08 2006