Pyramid #322
Generating function
$$U_{322}(x, y) = \frac{\sqrt{3} \left(- \sqrt{3 x y + \sin^{2}{\left(\frac{\operatorname{asin}{\left(\frac{3 \sqrt{3} \sqrt{x}}{2} \right)}}{3} \right)}} + \sin{\left(\frac{\operatorname{asin}{\left(\frac{3 \sqrt{3} \sqrt{x}}{2} \right)}}{3} \right)}\right)}{3 \sqrt{x}}$$
Explicit formula
$$T_{322}(n, m, k) = \begin{cases}0&\text{if m<k} ,\ \\\frac{\left(-1\right)^{m} k {\binom{- k + 2 m - 1}{m - 1}}}{m}&\text{if n=0} ,\ \\\frac{\left(-1\right)^{n} k \left(k - 2 m\right) {\binom{k - m - 1}{m - 1}} {\binom{- k + 2 m - 2 n - 1}{n - 1}}}{m n}&\text{if n>0} \end{cases} $$
Data table
0 -1 1 -2 5 -14 42
0 1 -3 1 -35 126 -462
0 2 -3 0 35 -252 1386
0 7 -1 1 0 42 -924
0 3 -42 5 -35 0 0
0 143 -198 252 -245 126 0
0 728 -1001 132 -147 1176 -462
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