$$U_{632}(x, y) = \frac{1 - \sqrt{1 - 4 y}}{2 y \sqrt{1 - 4 x}}$$

$$T_{632}(n, m, k) = \frac{4^{n} {\binom{\frac{k}{2} + n - 1}{n}} {\binom{k + 2 m - 1}{m}}}{k + m}$$