Pyramid #834
Generating function
$$U_{834}(x, y) = \frac{1}{\left(1 - y\right)^{4} \left(- \frac{x}{1 - y} + 1\right)}$$
Explicit formula
$$T_{834}(n, m, k) = {\binom{k + n - 1}{n}} {\binom{4 k + m + n - 1}{m}}$$
Data table
1 4 1 2 35 56 84
1 5 15 35 7 126 21
1 6 21 56 126 252 462
1 7 28 84 21 462 924
1 8 36 12 33 792 1716
1 9 45 165 495 1287 3003
1 1 55 22 715 2002 5005
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