A000474 - OEIS

This site is supported by donations to The OEIS Foundation.

A000474

Number of nonisomorphic 1-factorizations of K_{2n}.

1, 1, 1, 6, 396, 526915620, 1132835421602062347 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,4`
	COMMENTS	`Number of essentially different ways of scheduling a tournament of 2n teams.`
	REFERENCES	`CRC Handbook of Combinatorial Designs (see pages 655, 720-723).` `Dinitz, Jeffrey H.; Garnick, David K.; McKay, Brendan D.; There are 526,915,620 nonisomorphic one-factorizations of K_{12}. J. Combin. Des. 2 (1994), no. 4, 273-285.` `Petteri Kaski and Patric R. J. Ostergard, There are 1,132,835,421,602,062,347 nonisomorphic one-factorizations of K_{14}, Journal of Combinatorial Designs 17 (2009), pp. 147-159.` `Seah, E. and Stinson, D. R., On the enumeration of one-factorizations of complete graphs containing prescribed automorphism groups. Math. Comp. 50 (1988), 607-618.` `W. D. Wallis, 1-Factorizations of complete graphs, pp. 593-631 in J. H. Dinitz and D R. Stinson, Contemporary Design Theory, Wiley, 1992.`
	LINKS	`Petteri Kaski and Patric R. J. Ostergard, There are 1,132,835,421,602,062,347 nonisomorphic one-factorizations of K_{14}` `Joseph Malkevitch, Mathematics and Sports` `Index entries for sequences related to tournaments`
	FORMULA	`a(n) ~ exp(2n^2 log(2n)) as n -> infinity (see CRC Handbook, p. 655, Theorem 4.20).`
	CROSSREFS	`Cf. A000438.` `Sequence in context: A162137 A119645 A058807 * A029591 A151578 A172227` `Adjacent sequences: A000471 A000472 A000473 * A000475 A000476 A000477`
	KEYWORD	`nonn,hard,nice`
	AUTHOR	`N. J. A. Sloane (njas(AT)research.att.com).`
	EXTENSIONS	`a(7) communicated by Vesa Linja-aho (vesa.linja-aho(AT)tkk.fi), Aug 02 2008` `Comment, link, and update by Charles R Greathouse IV (charles.greathouse(AT)case.edu), May 11 2010`

Content is available under The OEIS End-User License Agreement .

Last modified February 15 20:03 EST 2012. Contains 205852 sequences.