0,0)$, we find that $$\begin{gathered} F(a):= {  \begingroup   \begingroup\lccode`~=`,     \lowercase{\endgroup\def~}{\pFcomma\mkern\pFqskip}  \mathcode`,=\string"0000   {}_{}F_{0}\biggl(\genfrac..{0pt}{}{a;0a,0-0a}{a+0/0};\frac{00}{00}, \frac{00}{00}\biggr)  \endgroup }