Pyramid #510
Generating function
$$U_{510}(x, y) = \frac{y^{4} \left(2 - 2 \sqrt{- \frac{x \left(- 2 y - \sqrt{1 - 4 y} + 1\right)^{3}}{2 y^{6}} + 1}\right)}{x \left(- 2 y - \sqrt{1 - 4 y} + 1\right)^{2}}$$
Explicit formula
$$T_{510}(n, m, k) = \frac{k \left(k + 3 n\right) {\binom{k + 2 n}{n}} {\binom{2 k + 2 m + 6 n}{m}}}{\left(k + 2 n\right) \left(k + m + 3 n\right)}$$
Data table
1 2 5 14 42 132 429
1 8 44 208 91 3808 15504
2 28 238 1596 931 49588 24794
5 1 115 1 73125 47502 283185
14 364 5278 5642 496496 3811808 26444418
42 1344 2352 298368 3070704 27221376 215621952
132 5016 102828 1509816 1779426 178935768 1594155024
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