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A002638 a(n) = (number of nonisomorphic nontransitive prime tournaments on n nodes) - Moebius(n).
(Formerly M0913 N0345)
-1, 1, 2, 3, 12, 52, 456, 6873, 191532, 9733032, 903753248, 154108311046, 48542114686912, 28401423719121392, 31021002160355166800, 63530415842308265086523, 244912778438520759443245824, 1783398846284777975419599903948 (list; graph; refs; listen; history; text; internal format)



N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


Table of n, a(n) for n=1..18.

J. W. Moon and M. Goldberg, On the composition of two tournaments, Duke Mathematical Journal, vol.37, no.2 (1970), pp.323-332. (subscription required)

J. W. Moon and M. Goldberg, On the composition of two tournaments, Duke Mathematical Journal 37.2 (1970): 323-332. [Annotated scans of pages 331 and 332 only]

Index entries for sequences related to tournaments


a(1)=-1, a(n) = A000568(n) - Sum_{d|n, d!=1, d!=n} (a(d) * A000568(n / d). - Sean A. Irvine, Oct 19 2015


Cf. A000568, A008683.

Sequence in context: A232864 A307957 A307956 * A027072 A083746 A025231

Adjacent sequences:  A002635 A002636 A002637 * A002639 A002640 A002641




N. J. A. Sloane


Definition clarified by N. J. A. Sloane, Jun 23 2015

More terms from Sean A. Irvine, Oct 19 2015



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Last modified December 14 09:41 EST 2019. Contains 329979 sequences. (Running on oeis4.)