Pyramid #367
Generating function
$$U_{367}(x, y) = - \frac{\sqrt{4 x + \frac{1}{\left(1 - y\right)^{2}}}}{2} + \frac{1}{2 - 2 y}$$
Explicit formula
$$T_{367}(n, m, k) = \begin{cases}0&\text{if n<k} ,\ \\- \frac{k {\binom{k - n - 1}{n - 1}} {\binom{k + m - 2 n - 1}{m}}}{n} \end{cases} $$
Data table
0 0 0 0 0 0 0
-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
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