Generating function
$$U_{1417}(x, y) = \frac{1}{\left(1 - x\right)^{3} \left(- \frac{y}{1 - x} + 1\right)}$$
Explicit formula
$$T_{1417}(n, m, k) = {\binom{k + m - 1}{m}} {\binom{3 k + m + n - 1}{n}}$$
Data table
1 1 1 1 1 1 1
3 4 5 6 7 8 9
6 1 15 21 28 36 45
1 2 35 56 84 12 165
15 35 7 126 21 33 495
21 56 126 252 462 792 1287
28 84 21 462 924 1716 3003
Export
expand_less