A260511 Number of signed permutations of length n that are sortable to the identity permutation by some sequence of cdr (context-directed reversal) moves.

1, 3, 15, 120, 1227, 15188

Offset: 1

Author

Caleb Stanford, Jul 27 2015

Keywords

• nonn
• more

Examples

			a(2) = 3 because [1,2], [-1,2], and [1,-2] are sortable to the identity [1,2] using only context-directed reversal moves.
		

Links

• 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.

Crossrefs

A249165 gives the number of unsigned permutations sortable by context-directed swaps; this is the analog for signed permutations and context-directed reversals.

A260506 gives the number of signed permutations sortable by both cdr and cds moves together. This sequence is therefore always bounded by A260506.

A000165 counts the total number of signed permutations.