In case any of you is bored on this Wednesday...
For example, choose 4 from [1,2,3]:
1232 3212 1212 ...
By "one-step removed," I mean if the element is
x, then the adjacent element is greater than zero and less than or equal to
n, and is either
x + 1 or
x - 1
I'm totally clueless about how to solve this.