
Combinations

Choosing $\displaystyle x$ elements out of set of $\displaystyle n$ elements ($\displaystyle z_1, ..., z_n$) and disregarding their order is the definition of combinations.
$\displaystyle F(x, z_1, ..., z_n) = \frac{n(n1)...(nx+1)}{x!}=\frac{n!}{(nx)!x!}={n \choose x}$

Except you obviously haven't read my post at all. That's not what I'm after. I'm fairly sure I explained what I'm looking for fairly clearly.
Ok, you've shown how many different terms the function http://www.mathhelpforum.com/mathhe...802e72e41.gif will have in terms of x and n. It isn't a formula that will calculate the value of each term and add them together.
Could somebody please read my post and help me with this?