8・33 The sequence of real numbers $a_{1}, a_{2}, \cdots, a_{n}, \cdots$ is defined by the following equation:
$$a_{n+1}=2^{n}-3 a_{n}, n=0,1,2, \cdots$$
(1) Find the expression for $a_{n}$ in terms of $a_{0}$ and $n$.
(2) Find $a_{0}$ such that for any positive integer $n, a_{n+1}>a_{n}$.