$$U_{1356}(x, y) = \frac{2 \sqrt{3} \sin{\left(\frac{\operatorname{asin}{\left(\frac{3 \sqrt{3} \sqrt{\frac{x}{1 - 4 y}}}{2} \right)}}{3} \right)}}{3 \sqrt{\frac{x}{1 - 4 y}} \sqrt{1 - 4 y}}$$

$$T_{1356}(n, m, k) = \frac{4^{m} k {\binom{k + 3 n - 1}{n}} {\binom{\frac{k}{2} + m + n - 1}{m}}}{k + 2 n}$$