Pyramid #470
Generating function
$$U_{470}(x, y) = \frac{\sqrt{y \left(4 - \frac{16 \sin^{2}{\left(\frac{\operatorname{asin}{\left(\frac{3 \sqrt{3} \sqrt{- x}}{2} \right)}}{3} \right)}}{3}\right) + 1}}{2} + \frac{1}{2}$$
Explicit formula
$$T_{470}(n, m, k) = \begin{cases}1&\text{if m=0, n=0} ,\ \\\frac{\left(-1\right)^{m - 1} k {\binom{- k + 2 m - 1}{m - 1}}}{m}&\text{if m>0, n=0} ,\ \\\frac{\left(-1\right)^{m - 1} \left(-1\right)^{n - 1} k {\binom{- k + 2 m - 1}{m - 1}} {\binom{- m + 3 n - 1}{n - 1}}}{n} \end{cases} $$
Data table
1 1 -1 2 -5 14 -42
0 1 -2 6 -2 7 -252
0 -2 3 -6 1 0 -126
0 7 -1 2 -4 7 -84
0 -3 42 -84 175 -35 63
0 143 -198 396 -84 1764 -3528
0 -728 1001 -2002 429 -924 19404
Export
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