Pyramid #40
Generating function
$$U_{40}(x, y) = \frac{y}{2} + \frac{\sqrt{4 x + y^{2} + 2 y + 1}}{2} + \frac{1}{2}$$
Explicit formula
$$T_{40}(n, m, k) = \begin{cases}1&\text{if n=0,m=0} ,\ \\\frac{k {\binom{m + n}{m}} {\binom{k - n - 1}{m + n - 1}}}{m + n} \end{cases} $$
Data table
1 1 0 0 0 0 0
1 -1 1 -1 1 -1 1
-1 3 -6 1 -15 21 -28
2 -1 3 -7 14 -252 42
-5 35 -14 42 -105 231 -462
14 -126 63 -231 693 -18018 42042
-42 462 -2772 12012 -42042 126126 -336336
Export
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