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