Generating function
$$U_{1444}(x, y) = \frac{\left(y + 1\right)^{3}}{\left(- x \left(y + 1\right)^{2} + 1\right)^{3}}$$
Explicit formula
$$T_{1444}(n, m, k) = {\binom{3 k + 2 n}{m}} {\binom{3 k + n - 1}{n}}$$
Data table
1 3 3 1 0 0 0
3 15 3 3 15 3 0
6 42 126 21 21 126 42
1 9 36 84 126 126 84
15 165 825 2475 495 693 693
21 273 1638 6006 15015 27027 36036
28 42 294 1274 3822 84084 14014
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