Pyramid #84
Generating function
$$U_{84}(x, y) = \frac{- \sqrt{4 x + 1} - 1}{y \left(\sqrt{4 x + 1} + 1\right) - 2}$$
Explicit formula
$$T_{84}(n, m, k) = \begin{cases}{\binom{k + m - 1}{m}}&\text{if n=0} ,\ \\\frac{\left(-1\right)^{n - 1} \left(k + m\right) {\binom{k + m - 1}{m}} {\binom{- k - m + 2 n - 1}{n - 1}}}{n}&\text{if n>0} \end{cases} $$
Data table
1 1 1 1 1 1 1
1 2 3 4 5 6 7
-1 -1 0 2 5 9 14
2 2 1 0 0 2 7
-5 -5 -3 -1 0 0 0
14 14 9 4 1 0 0
-42 -42 -28 -14 -5 -1 0
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