$$U_{1085}(x, y) = \frac{\left(1 - \sqrt{1 - 4 y}\right)^{2} \left(- 2 x - \sqrt{1 - 4 x} + 1\right)^{2}}{16 x^{4} y^{2}}$$

$$T_{1085}(n, m, k) = \frac{4 k^{2} {\binom{4 k + 2 n}{n}} {\binom{2 k + 2 m - 1}{m}}}{\left(2 k + m\right) \left(2 k + n\right)}$$