%I #7 Feb 18 2017 08:23:12
%S 1,1,2,6,24,96,504,3216,24024,177816,1538424,15108216,165392664,
%T 1793999256,21693217464,288019921656,4154515368024,59434596913656,
%U 924041894967864,15469081577068056,276917744041735704,4921195271561687256,93549435117715431864
%N Number of acyclic orientations of the Turán graph T(n,4).
%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="/A267384/b267384.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! / (3 * (1-log(4/3))^(3/2) * 4^n * (log(4/3))^(n+1)). - _Vaclav Kotesovec_, Feb 18 2017
%Y Column k=4 of A267383.
%K nonn
%O 0,3
%A _Alois P. Heinz_, Jan 13 2016