$$U_{984}(x, y) = \frac{\left(y + 1\right)^{2} \left(\sqrt{4 x \left(y + 1\right) + 1} + 1\right)}{2}$$

$$T_{984}(n, m, k) = \begin{cases}\frac{\left(-1\right)^{n - 1} k {\binom{2 k + n}{m}} {\binom{- k + 2 n - 1}{n - 1}}}{n}&\text{if n>0} ,\ \\{\binom{2 k + n}{m}}&\text{if n==0} \end{cases} $$