Hi,

Imagine I got the following series:

$\displaystyle f(\alpha)=(n!/\alpha!)\sum_{i=0}^n(-1)^{(i-\alpha)}u^i/[(i-\alpha)!(n-i)!]$

In which u$\displaystyle \in$[0,1] (and u$\displaystyle \in$ REAL)

While $\displaystyle \alpha$ and i and n are INTEGERS

The (-1)^something causes an alternating sign, in this way the sum doesn't explode, but seems to end up with a real number between 0 and 1,

adding something big, substracting something even bigger and so on...

(In case the factorial of a negative number is needed, for example in (i-$\displaystyle \alpha$)! this is set to 1.

The problem is that I need to compute the result of this series for large n (say 10000) and my computer breaks down on n! (of couse) for large n.

Is there an easier way to get to a result without computer overflow?

Thanks,

Gerrit