$$U_{99}(x, y) = \frac{1}{\sqrt{- 4 x^{2} + \left(y - 1\right)^{2}}}$$

$$T_{99}(n, m, k) = 2^{n - 1} \left(\left(-1\right)^{n} + 1\right) {\binom{\frac{k}{2} + \frac{n}{2} - 1}{\frac{n}{2}}} {\binom{k + m + n - 1}{m}}$$