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 A064626 Football tournament numbers: the number of possible point series for a tournament of n teams playing each other once where 3 points are awarded to the winning team and 1 to each in the case of a tie. 7
 1, 2, 7, 40, 355, 3678, 37263, 361058, 3403613, 31653377, 292547199, 2696619716 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS This sequence reflects the now common 3-point rule of international football where the sum of total points awarded depends on the outcome of each match. The classical 2-point rule is equivalent to that for chess tournaments (A007747). LINKS Table of n, a(n) for n=1..12. A. Ivanyi, L. Lucz, T. Matuszka, and S. Pirzada, Parallel enumeration of degree sequences of simple graphs, Acta Univ. Sapientiae, Informatica, 4, 2 (2012) 260-288. - From N. J. A. Sloane, Feb 15 2013 Wikipedia, Three points for a win EXAMPLE For 2 teams there are 2 possible outcomes: [0, 3] and [1, 1], so a(2) = 2. For 3 teams the outcomes are [0, 3, 6], [1, 3, 4], [3, 3, 3], [1, 1, 6], [1, 2, 4], [0, 4, 4] and [2, 2, 2], so a(3) is 7. Note that the outcome [3, 3, 3] can be obtained in two ways: (A beats B, B beats C, C beats A) or (B beats A, A beats C, C beats B). CROSSREFS Cf. A007747, A047730, A064422, A152789. Sequence in context: A319945 A132785 A224677 * A137731 A363004 A008608 Adjacent sequences: A064623 A064624 A064625 * A064627 A064628 A064629 KEYWORD nonn,nice,more,hard AUTHOR Thomas Schulze (jazariel(AT)tiscalenet.it), Sep 30 2001 EXTENSIONS a(8) and a(9) from Jon E. Schoenfield, May 05 2007 a(10) from Ming Li (dawnli(AT)ustc.edu), Jun 20 2008 a(11) from Jon E. Schoenfield, Sep 04 2008 a(12) from Jon E. Schoenfield, Dec 12 2008 STATUS approved

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Last modified August 12 13:23 EDT 2024. Contains 375108 sequences. (Running on oeis4.)