$$U_{958}(x, y) = \frac{- x y - \sqrt{x^{2} y^{2} - 4 x^{2} - 2 x y + 1} + 1}{2 x^{2}}$$

$$T_{958}(n, m, k) = \begin{cases}\frac{k {\binom{k + n}{\frac{m}{2} + \frac{n}{2}}} {\binom{\frac{m}{2} + \frac{n}{2}}{m}}}{k + n}&\text{if n + m even} ,\ \\0 \end{cases} $$