14. If the function $f ( x ) = \left\{ \begin{array} { l } - x + 6 , x \leq 2 , \\ 3 + \log _ { a } x , x > 2 , \end{array} ( a > 0 \right.$ and $a \neq 1 )$ has range $[ 4 , + \infty )$, then the range of the real number $a$ is $\_\_\_\_$.
14. If the function $f ( x ) = \left\{ \begin{array} { l } - x + 6 , x \leq 2 , \\ 3 + \log _ { a } x , x > 2 , \end{array} ( a > 0 \right.$ and $a \neq 1 )$ has range $[ 4 , + \infty )$, then the range of the real number $a$ is $\_\_\_\_$.