$$U_{139}(x, y) = \frac{- 2 x - y - \sqrt{- 4 x + y^{2} - y \left(2 - 4 x\right) + 1} + 1}{2 x^{2}}$$

$$T_{139}(n, m, k) = \begin{cases}\frac{k {\binom{k + 2 m - 1}{m}}}{k + m}&\text{if n=0} ,\ \\\frac{k {\binom{2 k + 2 n}{n}} {\binom{k + m + n}{m}}}{k + m + n} \end{cases} $$