Pyramid #12
Generating function
$$U_{12}(x, y) = \frac{y + 1}{- x y - x + 1}$$
Explicit formula
$$T_{12}(n, m, k) = \frac{k {\binom{k + n}{m}} {\binom{k + n}{n}}}{k + n}$$
Data table
1 1 0 0 0 0 0
1 2 1 0 0 0 0
1 3 3 1 0 0 0
1 4 6 4 1 0 0
1 5 1 1 5 1 0
1 6 15 2 15 6 1
1 7 21 35 35 21 7
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