Pyramid #424
Generating function
$$U_{424}(x, y) = \frac{2 x y - x - \sqrt{x^{2} - 4 x y + 2 x + 1} - 1}{2 y - 2}$$
Explicit formula
$$T_{424}(n, m, k) = \begin{cases}1&\text{if m=0,n=0} ,\ \\{\binom{k}{n}}&\text{if m=0} ,\ \\\frac{\left(-1\right)^{m - 1} k {\binom{- k + n - 1}{m - 1}} {\binom{k - m - 1}{n}}}{m} \end{cases} $$
Data table
1 1 1 1 1 1 1
1 -1 -1 -1 -1 -1 -1
0 1 0 0 0 0 0
0 -1 2 0 0 0 0
0 1 -5 5 0 0 0
0 -1 9 -21 14 0 0
0 1 -14 56 -84 42 0
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