Pyramid #774
Generating function
$$U_{774}(x, y) = \frac{\left(y + 1\right)^{3}}{\left(- x + y + 1\right)^{2}}$$
Explicit formula
$$T_{774}(n, m, k) = {\binom{k - n}{m}} {\binom{2 k + n - 1}{n}}$$
Data table
1 1 0 0 0 0 0
2 0 0 0 0 0 0
3 -3 3 -3 3 -3 3
4 -8 12 -16 2 -24 28
5 -15 3 -5 75 -105 14
6 -24 6 -12 21 -336 504
7 -35 105 -245 49 -882 147
Export
expand_less