The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.



Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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)



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.


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.


Sequence in context: A125617 A197969 A121452 * A304598 A171756 A235385

Adjacent sequences:  A249162 A249163 A249164 * A249166 A249167 A249168




Bridget Tenner, Dec 15 2014


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



Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

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