$$U_{914}(x, y) = \frac{x}{2} + \frac{\sqrt{x^{2} + 2 x + y \left(8 x + 8\right) + 1}}{2} + \frac{1}{2}$$

$$T_{914}(n, m, k) = \begin{cases}\left(-1\right)^{m} {\binom{k}{n}}&\text{if m==0} ,\ \\\frac{2^{m} k {\binom{k - m}{n}} {\binom{k - m - 1}{m - 1}}}{m}&\text{if m>0} ,\ \\1&\text{if n==0, m==0} \end{cases} $$