$$U_{361}(x, y) = \frac{- 2 y - \sqrt{- 4 x y^{2} - 4 y + 1} + 1}{2 y^{2}}$$

$$T_{361}(n, m, k) = \frac{k {\binom{k + m}{n}} {\binom{2 k + 2 m - 2 n}{m}}}{k + m}$$