$$U_{14}(x, y) = \frac{- x - y - \sqrt{x^{2} - 2 x + y^{2} + y \left(- 2 x - 2\right) + 1} + 1}{2 x y}$$

$$T_{14}(n, m, k) = \frac{k {\binom{k + m + n}{m}} {\binom{k + m + n}{n}}}{k + m + n}$$