# Figure-It-Out Function! - Part 3: The Powers of Factorials

Algebra Level 4

Let there be a function $$f(x):\mathbb{Z}\rightarrow \mathbb{Z}$$ with the following conditions

$\begin{cases}{f(x+1)=f(x)+(f(x))!} \\ {f(3)=28}\end{cases}$

Evaluate $$\displaystyle \sum_{i=-1}^{4} \left [ f(i) \cdot f(3-i) \right ]$$

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