

A051337


Number of strongly connected tournaments on n nodes.


3



1, 1, 0, 1, 1, 6, 35, 353, 6008, 178133, 9355949, 884464590, 152310149735, 48234782263293, 28304491788158056, 30964247546702883729, 63468402142317299907481, 244785748571033855024746438, 1782909084196274276970660380187, 24602074618353524534591008760307017
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OFFSET

0,6


COMMENTS

A tournament is strongly connected (or strong) if there is a directed path between any pair of points.


REFERENCES

F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 127, Eq. (5.2.4);
J. L. Gross and J. Yellen, eds., Handbook of Graph Theory, CRC Press, 2004; p. 523.


LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..50
John W. Moon, Topics on tournaments, Holt, Rinehard and Winston (1968)
Peter Steinbach, Field Guide to Simple Graphs, Volume 4, Part 11 (For Volumes 1, 2, 3, 4 of this book see A000088, A008406, A000055, A000664, respectively.)


FORMULA

G.f.: = 2  1/B(x) where B(x) = g.f. for A000568.


CROSSREFS

Cf. A000568, A054946.
Sequence in context: A261080 A291595 A268139 * A267224 A192996 A192997
Adjacent sequences: A051334 A051335 A051336 * A051338 A051339 A051340


KEYWORD

nonn,nice,easy


AUTHOR

Vladeta Jovovic


EXTENSIONS

a(0)=1 prepended and a(18)a(19) from Andrew Howroyd, Sep 10 2018


STATUS

approved



