Generating function
$$U_{1442}(x, y) = \frac{\left(y + 1\right)^{3}}{\left(- x \left(y + 1\right) + 1\right)^{3}}$$
Explicit formula
$$T_{1442}(n, m, k) = {\binom{3 k + n}{m}} {\binom{3 k + n - 1}{n}}$$
Data table
1 3 3 1 0 0 0
3 12 18 12 3 0 0
6 3 6 6 3 6 0
1 6 15 2 15 6 1
15 105 315 525 525 315 105
21 168 588 1176 147 1176 588
28 252 1008 2352 3528 3528 2352
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