$$U_{1441}(x, y) = \frac{\left(y + 1\right)^{2}}{\left(- x \left(y + 1\right) + 1\right)^{3}}$$

$$T_{1441}(n, m, k) = {\binom{2 k + n}{m}} {\binom{3 k + n - 1}{n}}$$