Pyramid #1391
Pyramid #1392
Pyramid #1393
Generating function
$$U_{1392}(x, y) = \frac{\frac{y}{1 - x} + 1}{\left(1 - x\right)^{3}}$$
Explicit formula
$$T_{1392}(n, m, k) = {\binom{k}{m}} {\binom{3 k + m + n - 1}{n}}$$
Data table
1 1 0 0 0 0 0
3 4 0 0 0 0 0
6 1 0 0 0 0 0
1 2 0 0 0 0 0
15 35 0 0 0 0 0
21 56 0 0 0 0 0
28 84 0 0 0 0 0
Related
Pyramid #1413: Change x y
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