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A255599 Number of (semi-)regular tournaments of order n. 0
1, 1, 1, 1, 1, 5, 3, 85, 15, 13333, 1223, 19434757, 1495297, 276013571133, 18400989629 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

COMMENTS

A tournament of odd order n is regular if the out-degree of each vertex is (n-1)/2. A tournament of even order n is semi-regular if the out-degree of each vertex is n/2-1 or n/2.

LINKS

Table of n, a(n) for n=1..15.

B. McKay, Digraphs

CROSSREFS

Cf. A000568, A096368.

Sequence in context: A257935 A109254 A258091 * A145985 A180403 A267512

Adjacent sequences:  A255596 A255597 A255598 * A255600 A255601 A255602

KEYWORD

nonn,hard,more

AUTHOR

Danny Rorabaugh, Feb 27 2015

EXTENSIONS

a(1)-a(2) prepended and a(14)-a(15) added by Brendan McKay, Mar 21 2019

STATUS

approved

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Last modified May 19 04:06 EDT 2019. Contains 323377 sequences. (Running on oeis4.)