The sequence $$a_1, a_2, \ldots$$ is geometric with $$a_1=a$$ and common ratio $$r,$$ where $$a$$ and $$r$$ are positive integers. Given that $$\log_8 a_1+\log_8 a_2+\cdots+\log_8 a_{12} = 2006,$$ find the number of possible ordered pairs $$(a,r).$$

(第二十四届AIME1 2006 第9题)