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Order of the subgroup of the symmetric group S_n generated by the cycles (1,3) and (1,2,3,...,n).

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6, 8, 120, 72, 5040, 1152, 362880, 28800, 39916800, 1036800, 6227020800, 50803200, 1307674368000, 3251404800, 355687428096000, 263363788800, 121645100408832000, 26336378880000, 51090942171709440000 (list; graph; listen)

	OFFSET	`3,1`
	FORMULA	`If n is odd a(n) = n!, if n is even a(n) = 2 * ((n/2)!)^2 = 2 * n! / A000984(n/2) = 2 * A001044(n/2).`
	CROSSREFS	`Cf. A000984, A070734, A000142, A009445, A001044.` `Adjacent sequences: A069657 A069658 A069659 this_sequence A069661 A069662 A069663` `Sequence in context: A013237 A013234 A013240 this_sequence A119001 A013239 A013235`
	KEYWORD	`nonn,easy`
	AUTHOR	`Sharon Sela (sharonsela(AT)hotmail.com), May 16 2002`
	EXTENSIONS	`More terms from Benoit Cloitre (benoit7848c(AT)orange.fr), May 20 2002`

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Last modified October 11 09:12 EDT 2008. Contains 144832 sequences.

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