Pyramid #178
Generating function
$$U_{178}(x, y) = x + \frac{y}{2} + \frac{\sqrt{4 x + y^{2} + 2 y + 1}}{2} + \frac{1}{2}$$
Explicit formula
$$T_{178}(n, m, k) = \begin{cases}1&\text{if n=0,m=0} ,\ \\\frac{\left(-1\right)^{n} \left(-1\right)^{m - 1} k {\binom{- 2 k + m + 2 n}{n}} {\binom{- k + m + n - 1}{m - 1}}}{m}&\text{if m>0} ,\ \\\frac{2 \left(-1\right)^{n - 1} k {\binom{- 2 k + 2 n - 1}{n - 1}}}{n}&\text{if m=0} \end{cases} $$
Data table
1 1 0 0 0 0 0
2 -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
expand_less