$$U_{947}(x, y) = \frac{\left(x + y\right)^{4}}{1 - x}$$

$$T_{947}(n, m, k) = \begin{cases}{\binom{4 k}{m}} {\binom{- k + m + n - 1}{- 4 k + m + n}},\ \\m + n < 4 k&\text{if 0} \end{cases} $$