Pyramid #552
Generating function
$$U_{552}(x, y) = \frac{- y - 1}{x \left(y + 1\right)^{3} - 1}$$
Explicit formula
$$T_{552}(n, m, k) = {\binom{k + 3 n}{m}} {\binom{k + n - 1}{n}}$$
Data table
1 1 0 0 0 0 0
1 4 6 4 1 0 0
1 7 21 35 35 21 7
1 1 45 12 21 252 21
1 13 78 286 715 1287 1716
1 16 12 56 182 4368 8008
1 19 171 969 3876 11628 27132
Export
expand_less