Pyramid #465
Generating function
$$U_{465}(x, y) = \sqrt[3]{\frac{x \left(1 - y\right)}{2} + \frac{\sqrt{3} \sqrt{x \left(27 x + \frac{4}{\left(1 - y\right)^{4}}\right)} \left(1 - y\right)}{18} + \frac{1}{27 \left(1 - y\right)^{3}}} + \frac{1}{3 - 3 y} + \frac{1}{9 \left(1 - y\right)^{2} \sqrt[3]{\frac{x \left(1 - y\right)}{2} + \frac{\sqrt{3} \sqrt{x \left(27 x + \frac{4}{\left(1 - y\right)^{4}}\right)} \left(1 - y\right)}{18} + \frac{1}{27 \left(1 - y\right)^{3}}}}$$
Explicit formula
$$T_{465}(n, m, k) = \begin{cases}1&\text{if n=0 and m=0} ,\ \\\frac{\left(-1\right)^{m - 1} k {\binom{- k + n - 1}{m - 1}}}{m}&\text{if m>0 and n=0} ,\ \\\frac{k {\binom{k - 2 n - 1}{n - 1}} {\binom{k + m - 4 n - 1}{m}}}{n} \end{cases} $$
Data table
1 1 1 1 1 1 1
1 -3 3 -1 0 0 0
-2 14 -42 7 -7 42 -14
7 -77 385 -1155 231 -3234 3234
-3 45 -315 1365 -4095 9009 -15015
143 -2717 24453 -138567 554268 -1662804 3879876
-728 16744 -184184 1289288 -644644 24496472 -73489416
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