\[\mathbf{F}\left({a,b\atop a+b+\tfrac{1}{2}};z\right)=2^{a+b-(\ifrac{1}{2})}(-z%
)^{(-a-b+(\ifrac{1}{2}))/2}\*P^{-a-b+(\ifrac{1}{2})}_{a-b-(\ifrac{1}{2})}\left%
(\sqrt{1-z}\right),\]