Pyramid #524
Pyramid #525
Pyramid #526
Generating function
$$U_{525}(x, y) = x \left(y + 1\right)^{2} + \left(y + 1\right)^{3}$$
Explicit formula
$$T_{525}(n, m, k) = {\binom{k}{n}} {\binom{3 k - n}{m}}$$
Data table
1 3 3 1 0 0 0
1 2 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
Related
Pyramid #697: Right on x
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