Pyramid #594
Generating function
$$U_{594}(x, y) = \frac{4 - 4 \sqrt{- \frac{x \left(\sqrt{4 y + 1} + 1\right)^{4}}{4} + 1}}{x \left(\sqrt{4 y + 1} + 1\right)^{3}}$$
Explicit formula
$$T_{594}(n, m, k) = \begin{cases}\frac{k {\binom{k + 2 n - 1}{n}}}{k + n}&\text{if m==0} ,\ \\\frac{\left(-1\right)^{m - 1} k \left(k + 4 n\right) {\binom{k + 2 n - 1}{n}} {\binom{- k + 2 m - 4 n - 1}{m - 1}}}{m \left(k + n\right)}&\text{if m>0} \end{cases} $$
Data table
1 1 -1 2 -5 14 -42
1 5 5 0 0 1 -5
2 18 54 6 18 0 0
5 65 325 78 91 455 65
14 238 1666 6188 1309 15708 9996
42 882 7938 39984 12348 240786 294294
132 33 363 231 9405 255816 47124
Export
expand_less