Pyramid #575
Generating function
$$U_{575}(x, y) = \frac{\left(1 - \frac{4 \sin^{2}{\left(\frac{\operatorname{asin}{\left(\frac{3 \sqrt{3} \sqrt{- x}}{2} \right)}}{3} \right)}}{3}\right) \left(- 2 y - \sqrt{1 - 4 y} + 1\right)}{2 y^{2}}$$
Explicit formula
$$T_{575}(n, m, k) = \begin{cases}\frac{k {\binom{2 k + 2 m}{m}}}{k + m}&\text{if n==0} ,\ \\\frac{\left(-1\right)^{n - 1} k^{2} {\binom{2 k + 2 m}{m}} {\binom{- k + 3 n - 1}{n - 1}}}{n \left(k + m\right)}&\text{if n>0} \end{cases} $$
Data table
1 2 5 14 42 132 429
1 2 5 14 42 132 429
-2 -4 -10 -28 -84 -264 -858
7 14 35 98 294 924 3003
-30 -60 -150 -420 -1260 -3960 -12870
143 286 715 2002 6006 18876 61347
-728 -1456 -3640 -10192 -30576 -96096 -312312
Export
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