%I M2083
%S 1,2,15,316,16885,2174586,654313415,450179768312,696979588034313,
%T 2398044825254021110,18151895792052235541515,
%U 299782788128536523836784628,10727139906233315197412684689421
%N Number of nnode labeled acyclic digraphs with 1 outpoint.
%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).
%e a(2) = 2: o>o (2 ways)
%e a(3) = 15: o>o>o (6 ways) and
%e o ... o o>o
%e .\ . / . \ . /
%e . v v ... v v
%e .. o ..... o
%e (3 ways) (6 ways)
%Y Cf. A058876, A003026.
%K nonn
%O 1,2
%A _N. J. A. Sloane_.
%E More terms from _Vladeta Jovovic_, Apr 10 2001
