$$U_{136}(x, y) = \frac{2 x + y - \sqrt{4 x + y^{2} + y \left(4 x + 2\right) + 1} + 1}{2 x^{2}}$$

$$T_{136}(n, m, k) = \frac{\left(-1\right)^{m + n} k {\binom{2 k + 2 n}{n}} {\binom{k + m + n}{m}}}{k + m + n}$$