Simplifying expression in summation notation

Question

Can anyone provide some guidance on how to simplify this expression, if at all possible? Thank you.

$$\sum_{i=1}^{n} {n\choose i} (-1)^{i+1} 2^{n^2+2(n-i)}$$

Answer 1

Observe you have \begin{align} -2^{n^2} \sum^n_{i=1} \binom{n}{i}(-1)^i 4^{n-i} \end{align}