Let $a_n$ be a sequence with $a_0 = 1$ and defined recursively by
\[
a_{n+1} = \begin{cases}
a_n + 2 & \text{if } n \text{ is even},\\
2a_n & \text{if } n \text{ is odd.}
\end{cases}
\]
What are the last two digits of $a_{2015}$?

Let's think step by step and output the final answer within \boxed{}.
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