Pyramid #1110
Pyramid #1111
Pyramid #1112
Generating function
$$U_{1111}(x, y) = \left(\frac{x}{\left(1 - y\right)^{3}} + 1\right)^{2}$$
Explicit formula
$$T_{1111}(n, m, k) = {\binom{2 k}{n}} {\binom{m + 3 n - 1}{m}}$$
Data table
1 0 0 0 0 0 0
2 6 12 2 3 42 56
1 6 21 56 126 252 462
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 #1162: Right on x
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