A165539 - OEIS

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A165539

Number of permutations of length n which avoid the patterns 4213 and 3421.

1, 2, 6, 22, 88, 367, 1571, 6861, 30468, 137229, 625573, 2881230 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	REFERENCES	`Kremer, Darla and Shiu, Wai Chee; Finite transition matrices for permutations avoiding pairs of length four patterns. Discrete Math. 268 (2003), 171-183. MR1983276 (2004b:05006). See Table 1.`
	LINKS	`Wikipedia, Permutation classes avoiding two patterns of length 4.`
	EXAMPLE	`There are 22 permutations of length 4 which avoid these two patterns, so a(4)=22.`
	CROSSREFS	`Sequence in context: A032351 A165537 A165538 * A109033 A049135 A049127` `Adjacent sequences: A165536 A165537 A165538 * A165540 A165541 A165542`
	KEYWORD	`nonn,more,changed`
	AUTHOR	`Vince Vatter (vatter(AT)gmail.com), Sep 21 2009`

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Last modified February 16 17:11 EST 2012. Contains 205938 sequences.