OFFSET
1,2
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.
EXAMPLE
a(2) = 3 because [1,2], [-1,2], and [1,-2] are sortable to the identity [1,2] using only context-directed reversal moves.
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.
KEYWORD
nonn,more
AUTHOR
Caleb Stanford, Jul 27 2015
STATUS
approved