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A249165 Number of cds-sortable permutations in S_n. That is, number of permutations for which application of some sequence of context directed swaps ("cds" operations) terminates in the identity. 3
1, 1, 4, 13, 72, 390, 2880, 21672, 201600, 1935360, 21772800, 253756800, 3353011200, 45924278400 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..14.

K. L. M. Adamyk, E. Holmes, G. R. Mayfield, D. J. Moritz, M. Scheepers, B. E. Tenner, and H. C. Wauck, Sorting permutations: games, genomes, and cycles, arXiv:1410.2353 [math.CO], 2014.

C. A. Brown, C. S. Carrillo Vazquez, R. Goswami, S. Heil, M. Scheepers, The Sortability of Graphs and Matrices under Context Directed Swaps, arXiv:1904.03287 [math.CO], 2019.

EXAMPLE

a(3) = 4 because there are 4 cds-sortable permutations of {1,2,3}. These are, in one-line notation, 123, 132, 213, and 321.

CROSSREFS

Sequence in context: A125617 A197969 A121452 * A304598 A171756 A235385

Adjacent sequences:  A249162 A249163 A249164 * A249166 A249167 A249168

KEYWORD

nonn,more

AUTHOR

Bridget Tenner, Dec 15 2014

EXTENSIONS

a(11)-a(14) from Paul Plummer, Jan 18 2015

STATUS

approved

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Last modified December 1 20:54 EST 2020. Contains 338858 sequences. (Running on oeis4.)