Pyramid #1329
Pyramid #1330
Pyramid #1331
Generating function
$$U_{1330}(x, y) = x + \frac{1}{\left(1 - y\right)^{3}}$$
Explicit formula
$$T_{1330}(n, m, k) = {\binom{k}{n}} {\binom{3 k + m - 3 n - 1}{m}}$$
Data table
1 3 6 1 15 21 28
1 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
Related
Pyramid #1030: Right on x
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