

A061545


Number of pairexchange / setrotate sequences achieving the minimum length of A048200(n).


1



0, 2, 1, 1, 1, 2, 4, 16, 40, 512, 1472, 65536
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


LINKS



EXAMPLE

Let "r" denote rotation and "x" an exchange.
For n = 5, the shortest sequence reversing "ABCDE" has length A048200(5) = 10, the only sequence doing so is "xrrxrrxrxr", so a(5) = 1.
For n = 6, we have A048200(6) = 15, but there are 2 solutions of this length "xrxrrxrxrrxrrrx" and "rxrrxrxrrxrxrrx", so a(6) = 2.


CROSSREFS



KEYWORD

more,nonn


AUTHOR



EXTENSIONS



STATUS

approved



