$$ \Gamma (z) \sim z^{z - 1/2} e^{ - z} \sqrt {2\pi } \left( {1 + \frac{1}{{12z}} + \frac{1}{{288z^2 }} - \frac{{139}}{{51840z^3 }} - \frac{{571}}{{2488320z^4 }} + \cdots } \right). $$ Above, is a closed form for the gamma function.
Is there a closed form for the incomplete gamma function that is for $\Gamma(a,x)$?