
EXAMPLE

For n = 5 the a(5) = 40 solutions are one of following ten permutations, or a reversal, complement, or reversal and complement of one of these permutations:
[1,3,4,2,5]
[1,4,3,5,2]
[1,4,5,3,2]
[1,5,2,4,3]
[1,5,3,2,4]
[2,1,4,5,3]
[2,1,5,3,4]
[2,3,5,1,4]
[2,4,1,5,3]
[2,5,4,1,3]
As a nonexample, [1,5,4,2,3] does not satisfy the kth differences property, because while its first differences ([4,1,2,1]) and its second differences ([5,1,3]) are distinct, its third differences ([4,4]) are not.
