计算$\left|\begin{array}{cccccc}
a_0 & 1 & 1 & \cdots & 1 & 1 \\
1 & a_1 & 0 & \cdots & 0 & 0 \\
1 & 0 & a_2 & \cdots & 0 & 0 \\
\vdots & \vdots & \vdots & & \vdots & \vdots \\
1 & 0 & 0 & \cdots & a_{n-1} & 0 \\
1 & 0 & 0 & \cdots & 0 & a_n
\end{array}\right|, a_i \neq 0 \quad(i=1,2, \cdots, n)$