$$U_{168}(x, y) = \frac{1 - \sqrt{y \left(- 4 x^{3} - 12 x^{2} - 12 x - 4\right) + 1}}{2 y \left(x + 1\right)^{2}}$$

$$T_{168}(n, m, k) = \frac{k {\binom{k + 3 m}{n}} {\binom{k + 2 m - 1}{m}}}{k + m}$$