$$U_{959}(x, y) = \frac{- x^{2} - 1}{x y - 1}$$

$$T_{959}(n, m, k) = \begin{cases}\frac{k {\binom{k + m}{\frac{m}{2} + \frac{n}{2}}} {\binom{\frac{m}{2} + \frac{n}{2}}{m}}}{k + m}&\text{if n + m even} ,\ \\0 \end{cases} $$