Pyramid #622
Generating function
$$U_{622}(x, y) = \frac{\left(1 - \frac{4 \sin^{2}{\left(\frac{\arcsin{\left(\frac{3 \sqrt{3} \sqrt{- y}}{2} \right)}}{3} \right)}}{3}\right) \left(- 2 x - \sqrt{1 - 4 x} + 1\right)}{2 x^{2}}$$
Explicit formula
$$T_{622}(n, m, k) = \begin{cases}\frac{k {\binom{2 k + 2 n}{n}}}{k + n}&\text{if m=0 } ,\ \\\frac{\left(-1\right)^{m - 1} k^{2} {\binom{2 k + 2 n}{n}} {\binom{- k + 3 m - 1}{m - 1}}}{m \left(k + n\right)}&\text{if m>0} \end{cases} $$
Data table
1 1 -2 7 -3 143 -728
2 2 -4 14 -6 286 -1456
5 5 -1 35 -15 715 -364
14 14 -28 98 -42 2002 -10192
42 42 -84 294 -126 6006 -30576
132 132 -264 924 -396 18876 -96096
429 429 -858 3003 -1287 61347 -312312
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