Calculation of autocorrelation - does calculation "loop"?
You didn't specify for which values of $n$ your signal is not zero, so I'll assume that happens from $0$ to $4$. You have a finite sequence $x(n)$ such that

$$x(n) = 0 \qquad \forall n\in\mathbb{Z}:n&lt;0 \ \mathrm{or} \ n&gt;4$$

This means that $x(5)$, $x(6)$, etc. are equal to $0$. The same happens for $x(-1)$, $x(-2)$, and so on. Thus, products involving these quantities will be zero as well.