Given $n$ points on a graph, I want to know how many distinct paths can be formed that:
(1) start at one point and end at a different point
(2) never revisit a point [are acyclic]
Also two paths that traverse the same path but in reverse order are considered the same path.
Is there a closed form formula for calculating this given just $n$?
I believe an equivalent way to state this problem is: "how many distinct acyclic paths through a complete graph of size $n$ are there?"
I've gotten some leads here but haven't been able to find an answer yet