Tangent and normal are drawn at

Tangent and normal are drawn at $\mathrm{P}(16,16)$ on the parabola $\mathrm{y}^{2}=16 \mathrm{x}$, which intersect the axis of the parabola at $A$ and $B$, respectively. If $C$ is the centre of the circle through the points $\mathrm{P}, \mathrm{A}$ and $\mathrm{B}$ and $\angle \mathrm{CPB}=\theta$, then a value of $\tan \theta$ is-