%I

%S 1,3,12,62,370,2397,16345,115376,834786,6152285,45990120,347673108,

%T 2652283517,20385035972,157656007680,1225743120520,9572972899946,

%U 75056029550721,590469939950716,4659115833115680,36859770507695688

%N Number of components in all forests on nodes on a circle.

%F Sum(k*binomial(n, k-1)*binomial(3*n-2*k-1, n-k)/(2*n-k), k=1..n)

%K nonn

%O 1,2

%A _Emeric Deutsch_