I am aware that the formula for combinations is:

$$\binom{n}{r}=\frac{n!}{(n - r)! \:r!}$$

This gives me the numbers I want for combinations of a certain length.

However, in my case, I need the sum of these where *r* can be all the values between 1 and n.

Is there a simple formula for this (that is, something that can be put in a spreadsheet)?