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A053617 Number of permutations of length n which avoid the patterns 1234 and 1324. 2
1, 1, 2, 6, 22, 90, 396, 1837, 8864, 44074, 224352, 1163724, 6129840, 32703074, 176351644, 959658200, 5262988330, 29057961666, 161374413196, 900792925199, 5050924332096, 28434661250454, 160644331001476, 910455895039056, 5174722258676440, 29486753617569684 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

These permutations have an "enumeration scheme" of depth 4, see D. Zeilberger's article in the links.

G.f. conjectured to be non-D-finite (see Albert et al. link). - Jay Pantone, Oct 01 2015

LINKS

Andrew Baxter and Jay Pantone, Table of n, a(n) for n = 0..600 (terms n=1..100 from Andrew Baxter)

Michael H. Albert, Cheyne Homberger, Jay Pantone, Nathaniel Shar, Vincent Vatter, Generating Permutations with Restricted Containers, arXiv:1510.00269 [math.CO], (2015)

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.

Wikipedia, Permutation classes avoiding two patterns of length 4.

D. Zeilberger, Enumeration schemes and more importantly their automatic generation, Annals of Combinatorics 2 (1998) 185-195.

CROSSREFS

Cf. A032351, A053614, A106228, A165542, A165545, A257561, A257562.

Sequence in context: A103137 A165546 A279568 * A089449 A264601 A226435

Adjacent sequences:  A053614 A053615 A053616 * A053618 A053619 A053620

KEYWORD

nonn

AUTHOR

Moa Apagodu, Mar 20 2000

EXTENSIONS

More terms from Andrew Baxter, May 20 2011

STATUS

approved

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Last modified April 22 08:25 EDT 2019. Contains 322329 sequences. (Running on oeis4.)