Just. Another Summation

Algebra Level 4

\(\sum_{n=4}^{20} \frac{(n-4)!}{(n)!}\)

If the result of the summation above can be written in form \(\frac{a}{b}\) for \(a\) and \(b\) are positive, coprime integers, find \(a + b\)

×

Problem Loading...

Note Loading...

Set Loading...