$$U_{761}(x, y) = \frac{y^{4} \left(1 - \sqrt{- \frac{2 x \left(- 2 y - \sqrt{1 - 4 y} + 1\right)}{y^{2}} + 1}\right)^{3}}{2 x^{3} \left(- 2 y - \sqrt{1 - 4 y} + 1\right)^{2}}$$

$$T_{761}(n, m, k) = \frac{3 k \left(k + n\right) {\binom{3 k + 2 n}{n}} {\binom{2 k + 2 m + 2 n}{m}}}{\left(3 k + 2 n\right) \left(k + m + n\right)}$$