Pyramid #518
Generating function
$$U_{518}(x, y) = - \frac{\left(y + 1\right)^{6}}{x - \left(y + 1\right)^{4}}$$
Explicit formula
$$T_{518}(n, m, k) = {\binom{2 k - 4 n}{m}} {\binom{k + n - 1}{n}}$$
Data table
1 2 1 0 0 0 0
1 -2 3 -4 5 -6 7
1 -6 21 -56 126 -252 462
1 -1 55 -22 715 -2002 5005
1 -14 105 -56 238 -8568 27132
1 -18 171 -114 5985 -26334 100947
1 -22 253 -2024 1265 -6578 29601
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