$$U_{670}(x, y) = \frac{- 2 x - \sqrt{1 - 4 x} + 1}{2 x^{2} \sqrt{1 - 4 y}}$$

$$T_{670}(n, m, k) = \frac{4^{m} k {\binom{2 k + 2 n}{n}} {\binom{\frac{k}{2} + m - 1}{m}}}{k + n}$$