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A212433 Number of equivalence classes of S_n under transformations of positionally and numerically adjacent elements of the form abc <--> acb <--> bac <--> cba, where a<b<c. 0
1, 1, 2, 3, 13, 71, 470, 3497, 29203, 271500 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..9.

S. Linton, J. Propp, T. Roby, and J. West, Equivalence Classes of Permutations under Various Relations Generated by Constrained Transpositions, arXiv:1111.3920, 2011 [math.CO]

EXAMPLE

From Alois P. Heinz, Jun 23 2012: (Start)

a(3) = 3: {123, 132, 213, 321}, {231}, {312}.

a(4) = 13: {1234, 1243, 1324, 1432, 2134, 3214}, {1342}, {1423}, {2143}, {2314}, {2341, 2431, 3241, 4123, 4132, 4213, 4321}, {2413}, {3124}, {3142}, {3412}, {3421}, {4231}, {4312}.

a(5) = 71: {12345, 12354, 12435, 12543, 13245, 13254, 14325, 21345, 21354, 21435, 21543, 32145, 32154}, {12453}, ..., {53412}, {53421}, {54231}.

(End)

CROSSREFS

Cf. A212581.

Sequence in context: A219698 A293251 A061912 * A013167 A224239 A068096

Adjacent sequences:  A212430 A212431 A212432 * A212434 A212435 A212436

KEYWORD

nonn,more

AUTHOR

Tom Roby, Jun 21 2012

EXTENSIONS

a(8)-a(9) from Alois P. Heinz, Jun 23 2012

STATUS

approved

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Last modified December 15 04:33 EST 2018. Contains 318141 sequences. (Running on oeis4.)