$$U_{270}(x, y) = \frac{- 2 x y - 2 x - \sqrt{- 4 x y - 4 x + 1} + 1}{2 x^{2}}$$

$$T_{270}(n, m, k) = \frac{k {\binom{2 k + 2 n}{m + n}} {\binom{m + n}{n}}}{k + n}$$