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%I #7 Feb 18 2017 08:38:30
%S 1,1,2,6,24,120,720,5040,40320,362880,3265920,33022080,369774720,
%T 4536362880,60451816320,869007242880,13397819541120,220448163358080,
%U 3854801333416320,67295207974942080,1248445283166184320,24512281966435294080,507579925622189454720
%N Number of acyclic orientations of the Turán graph T(n,9).
%C An acyclic orientation is an assignment of a direction to each edge such that no cycle in the graph is consistently oriented. Stanley showed that the number of acyclic orientations of a graph G is equal to the absolute value of the chromatic polynomial X_G(q) evaluated at q=-1.
%H Alois P. Heinz, <a href="/A267389/b267389.txt">Table of n, a(n) for n = 0..450</a>
%H Richard P. Stanley, <a href="http://dx.doi.org/10.1016/0012-365X(73)90108-8">Acyclic Orientations of Graphs</a>, Discrete Mathematics, 5 (1973), pages 171-178, doi:10.1016/0012-365X(73)90108-8
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Tur%C3%A1n_graph">Turán graph</a>
%F a(n) ~ n! / (8 * (1 - log(9/8))^4 * 9^n * (log(9/8))^(n+1)). - _Vaclav Kotesovec_, Feb 18 2017
%Y Column k=9 of A267383.
%K nonn
%O 0,3
%A _Alois P. Heinz_, Jan 13 2016
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