Recursive Sequences

Fix $x \in \mathbb{R}$ and define a series recursively as follows: $$\begin{cases} a_0 = (x-1) \\ a_n = (a_{n-1})(a_{n-1} + 2) & \text{for } n \ge 1 \end{cases}$$ Which of the following is a closed-form formula for $a_n$?