Generating function
$$U_{1476}(x, y) = \frac{2 \sqrt{3} \sin{\left(\frac{\operatorname{asin}{\left(\frac{3 \sqrt{3} \sqrt{\frac{x}{\left(1 - y\right)^{3}}}}{2} \right)}}{3} \right)}}{3 \sqrt{\frac{x}{1 - y}} \left(1 - y\right)}$$
Explicit formula
$$T_{1476}(n, m, k) = \frac{k {\binom{k + 3 n - 1}{n}} {\binom{2 k + m + 3 n - 1}{m}}}{k + 2 n}$$
Data table
1 2 3 4 5 6 7
1 5 15 35 7 126 21
3 24 108 36 99 2376 5148
12 132 792 3432 12012 36036 96096
55 77 5775 308 1309 47124 149226
273 4641 41769 264537 1322685 5555277 20369349
1428 2856 29988 219912 1264494 60695712 2528988
Export
expand_less