Let P be n-sided regular polygon. How many contained polygons can be constructed from any subset of P's n vertices such that no pair of polygons are congruent.
I've struggled with this problem for some time and unfortunately failed to find solution nor guidance on how to approach this problem. My first idea was to divide calculate the result as sum of k-element subsets where
$$k \leq n$$
This approach did not lead me to a general formula, though is probably a start.