Pyramid #869
Generating function
$$U_{869}(x, y) = \frac{1 - \sqrt{- 4 x \left(1 - y\right)^{2} + 1}}{2 x \left(1 - y\right)^{5}}$$
Explicit formula
$$T_{869}(n, m, k) = \frac{k {\binom{k + 2 n - 1}{n}} {\binom{3 k + m - 2 n - 1}{m}}}{k + n}$$
Data table
1 3 6 1 15 21 28
1 1 1 1 1 1 1
2 -2 0 0 0 0 0
5 -15 15 -5 0 0 0
14 -7 14 -14 7 -14 0
42 -294 882 -147 147 -882 294
132 -1188 4752 -11088 16632 -16632 11088
Export
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