Generating function
$$U_{1474}(x, y) = \frac{2 \sqrt{3} \sin{\left(\frac{\operatorname{asin}{\left(\frac{3 \sqrt{3} \sqrt{\frac{x}{\left(1 - y\right)^{3}}}}{2} \right)}}{3} \right)}}{3 \sqrt{\frac{x}{\left(1 - y\right)^{3}}}}$$
Explicit formula
$$T_{1474}(n, m, k) = \frac{k {\binom{k + 3 n - 1}{n}} {\binom{m + 3 n - 1}{m}}}{k + 2 n}$$
Data table
1 0 0 0 0 0 0
1 3 6 1 15 21 28
3 18 63 168 378 756 1386
12 108 54 198 594 15444 36036
55 66 429 2002 75075 24024 68068
273 4095 3276 18564 83538 3174444 1058148
1428 25704 244188 162792 854658 37604952 144152316
Export
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