%I M4666
%S 1,9,198,10710,1384335,416990763,286992935964,444374705175516,
%T 1528973599758889005,11573608032229769067465,
%U 191141381932394665770442818,6839625961762363728765713227698
%N Number of nnode acyclic digraphs with 2 outpoints.
%D R. W. Robinson, Counting labeled acyclic digraphs, pp. 239273 of F. Harary, editor, New Directions in the Theory of Graphs. Academic Press, NY, 1973.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%Y Cf. A058876, A003025.
%K nonn
%O 2,2
%A _N. J. A. Sloane_.
%E More terms from _Vladeta Jovovic_, Apr 10 2001
