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.
Table of n, a(n) for n=1..15.
B. McKay, Digraphs
Cf. A000568, A096368.
Sequence in context: A257935 A109254 A258091 * A145985 A180403 A267512
Adjacent sequences: A255596 A255597 A255598 * A255600 A255601 A255602
Danny Rorabaugh, Feb 27 2015
a(1)-a(2) prepended and a(14)-a(15) added by Brendan McKay, Mar 21 2019