$$U_{352}(x, y) = \frac{- 2 x - \sqrt{1 - 4 x} + 1}{2 x^{2} \left(1 - y\right)^{3}}$$

$$T_{352}(n, m, k) = \frac{k {\binom{2 k + 2 n}{n}} {\binom{3 k + m - 1}{m}}}{k + n}$$