Hey every body... I have been trying to figure this out for quite a while now.... and i feel like i am making progress, but it just doesn't seem to be working. Imagine you have a string of numbers with a length of X N of those numbers must be 1 and X-N of those numbers must be zero. how many different combinations can i make? (if it matters the relationship between n and x is this... x=(n^2)-(2*n)) any help would be really appreciated.