A145208 Number of distinct shuffles of the identity permutation on n letters with the halfway-wrapped around permutation k+1,k+2,...,n-1,n,1,2,...,k where k=floor(n/2).

1, 4, 13, 54, 197, 792, 2977, 11750, 44744, 175066, 671783, 2619148, 10104590

Offset: 1

Author

Camillia Smith Barnes, Oct 04 2008

Keywords

• nonn

Comments

A complicated formula has been found but needs to be simplified before entering here; also, a Maple program is on the way.

Examples

			For n=2, the distinct shuffles of 12 with 21 are: 1221, 1212, 2112, 2121.
		

References

• C. Smith, dissertation, Harvard University, forthcoming.