Pyramid #551
Generating function
$$U_{551}(x, y) = x \left(y + 1\right)^{3} + y + 1$$
Explicit formula
$$T_{551}(n, m, k) = {\binom{k}{n}} {\binom{k + 2 n}{m}}$$
Data table
1 1 0 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