Is there any identity for this series?

Question

While solving inequality and finite series problem I often come across this series-

$$(n+1)(n+2)(n+3)...(n+n)$$.

Is there a general solution to this form of a series?

Thanks for any help!!

Answer 1

$\prod_{k = n + 1}^{2n} k = \frac{\prod_{k = n + 1}^{2n} k \prod_{k = 1}^{n} k}{\prod_{k = 1}^{n} k} = \frac{\prod_{k = 1}^{2n} k }{\prod_{k = 1}^{n} k} = \frac{(2n)!}{n!}$