$$U_{85}(x, y) = \frac{1 - \sqrt{y \left(- 4 x - 2\right) - 2 y \sqrt{4 x + 1} + 1}}{y \left(\sqrt{4 x + 1} + 1\right)}$$

$$T_{85}(n, m, k) = \begin{cases}1&\text{if n=0} ,\ \\\frac{\left(-1\right)^{n - 1} k \left(k + 2 m\right) {\binom{k + 2 m - 1}{m}} {\binom{- k - 2 m + 2 n - 1}{n - 1}}}{n \left(k + m\right)} \end{cases} $$