\[U_{n}\left(x\right)=C^{(1)}_{n}\left(x\right)=\ifrac{(n+1)P^{(\frac{1}{2},%
\frac{1}{2})}_{n}\left(x\right)}{P^{(\frac{1}{2},\frac{1}{2})}_{n}\left(1%
\right)},\]