Pyramid #847
Generating function
$$U_{847}(x, y) = \frac{1}{x y^{5} - 5 x y^{4} - x + y^{3} \left(10 x - 1\right) + y^{2} \left(3 - 10 x\right) + y \left(5 x - 3\right) + 1}$$
Explicit formula
$$T_{847}(n, m, k) = {\binom{k + n - 1}{n}} {\binom{3 k + m - 2 n - 1}{m}}$$
Data table
1 3 6 1 15 21 28
1 1 1 1 1 1 1
1 -1 0 0 0 0 0
1 -3 3 -1 0 0 0
1 -5 1 -1 5 -1 0
1 -7 21 -35 35 -21 7
1 -9 36 -84 126 -126 84
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