Pyramid #113
Generating function
$$U_{113}(x, y) = \frac{y - 1}{x + y - 1}$$
Explicit formula
$$T_{113}(n, m, k) = \begin{cases}1&\text{if n=0 and m=0} ,\ \\\frac{k {\binom{m + n}{n}} {\binom{k + n - 1}{k}}}{m + n} \end{cases} $$
Data table
1 0 0 0 0 0 0
1 1 1 1 1 1 1
1 2 3 4 5 6 7
1 3 6 1 15 21 28
1 4 1 2 35 56 84
1 5 15 35 7 126 21
1 6 21 56 126 252 462
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