The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A267386 Number of acyclic orientations of the Turán graph T(n,6). 2
 1, 1, 2, 6, 24, 120, 720, 4320, 30960, 256320, 2399760, 25022880, 287250480, 3284869680, 41344521840, 566715682800, 8391341277360, 133348995238320, 2262083352430320, 38232720235613520, 689864650481977200, 13221780471876281040, 268029961230742291440 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS 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. LINKS Alois P. Heinz, Table of n, a(n) for n = 0..450 Richard P. Stanley, Acyclic Orientations of Graphs, Discrete Mathematics, 5 (1973), pages 171-178, doi:10.1016/0012-365X(73)90108-8 Wikipedia, Turán graph FORMULA a(n) ~ n! / (5 * (1 - log(6/5))^(5/2) * 6^n * (log(6/5))^(n+1)). - Vaclav Kotesovec, Feb 18 2017 CROSSREFS Column k=6 of A267383. Sequence in context: A179358 A179365 A070947 * A215718 A060727 A152350 Adjacent sequences:  A267383 A267384 A267385 * A267387 A267388 A267389 KEYWORD nonn AUTHOR Alois P. Heinz, Jan 13 2016 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 31 07:14 EDT 2020. Contains 334747 sequences. (Running on oeis4.)