Pyramid #16
Generating function
$$U_{16}(x, y) = \frac{1 - \sqrt{- 4 x y^{2} - 8 x y - 4 x + 1}}{2 x \left(y + 1\right)}$$
Explicit formula
$$T_{16}(n, m, k) = \frac{k {\binom{k + 2 n}{m}} {\binom{k + 2 n}{n}}}{k + 2 n}$$
Data table
1 1 0 0 0 0 0
1 3 3 1 0 0 0
2 1 2 2 1 2 0
5 35 105 175 175 105 35
14 126 504 1176 1764 1764 1176
42 462 231 693 1386 19404 19404
132 1716 10296 37752 9438 169884 226512
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