$$U_{224}(x, y) = \frac{x - \sqrt{x^{2} + 2 y \sqrt{1 - 4 x} + y \left(4 x - 2\right)}}{2 x y}$$

$$T_{224}(n, m, k) = \frac{k {\binom{k + 2 m - 1}{m}} {\binom{2 k + 2 m + 2 n}{n}}}{k + m + n}$$