$$U_{992}(x, y) = \frac{1 - \sqrt{- \sqrt{2} x \sqrt{\frac{1 - \sqrt{1 - 16 y}}{y}} + 1}}{2 x}$$

$$T_{992}(n, m, k) = \begin{cases}1&\text{if n=0 , m=0 , k=0} ,\ \\\frac{4^{m} k {\binom{k + 2 n - 1}{n}} {\binom{\frac{k}{2} + 2 m + \frac{n}{2} - 1}{m}}}{k + 2 m + n}&\text{if k even} ,\ \\\frac{k {\binom{k + 2 n - 1}{n}} {\binom{\frac{k}{2} + 2 m + \frac{n}{2} - \frac{1}{2}}{m}} {\binom{k + 4 m + n - 1}{\frac{k}{2} + 2 m + \frac{n}{2} - \frac{1}{2}}}}{\left(k + 2 m + n\right) {\binom{k + 2 m + n - 1}{\frac{k}{2} + m + \frac{n}{2} - \frac{1}{2}}}}&\text{if k odd} \end{cases} $$