Difficult# Telescoping Series

SVCALC-JZ1B4W

What is the sum of the series:

$$\sum_{n=4}^\infty \frac{1}{n^2-2n-3}$$

*(Hint: Use partial fractions to rewrite $ \frac{1}{n^2-2n-3}$ as the difference of two fractions, and then show that the series is telescoping.)*