A045992 - OEIS

This site is supported by donations to The OEIS Foundation.

A045992

binomial(2n,n)-n; number of (weakly) increasing or decreasing maps from 1,...,n to 1,...,n.

1, 1, 4, 17, 66, 247, 918, 3425, 12862, 48611, 184746, 705421, 2704144, 10400587, 40116586, 155117505, 601080374, 2333606203, 9075135282, 35345263781, 137846528800, 538257874419, 2104098963698, 8233430727577, 32247603683076 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`0,3`
	LINKS	`Table of n, a(n) for n=0..24.`
	EXAMPLE	`a(3)=17 since can map (1,2,3) to (1,1,1), (1,1,2), (1,1,3), (1,2,2), (1,2,3), (1,3,3), (2,1,1), (2,2,1), (2,2,2), (2,2,3), (2,3,3), (3,1,1), (3,2,1), (3,2,2), (3,3,1), (3,3,2), or (3,3,3) but not for example to (1,3,2)`
	CROSSREFS	`Cf. A000312, A000984, A001700.` `Sequence in context: A181410 A102207 A202555 * A217539 A046723 A030529` `Adjacent sequences: A045989 A045990 A045991 * A045993 A045994 A045995`
	KEYWORD	`nonn`
	AUTHOR	`N. J. A. Sloane.`
	STATUS	`approved`

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

Last modified May 24 08:47 EDT 2013. Contains 225617 sequences.