Pyramid #985
Generating function
$$U_{985}(x, y) = \left(y + 1\right)^{2} \left(x \left(y + 1\right) + 1\right)$$
Explicit formula
$$T_{985}(n, m, k) = {\binom{k}{n}} {\binom{2 k + n}{m}}$$
Data table
1 2 1 0 0 0 0
1 3 3 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
Export
expand_less