105 people pass the ball to each other, requiring that after receiving the ball, one must pass it to someone else immediately, starting with person A for the first pass. Then, the number of different ways the ball can be passed back to A after 4 passes is . $\qquad$
1052 Prompt: Let the number of different ways 5 people can be arranged according to this rule for $n$ times be $a_{n}$, then $a_{1}=0, a_{2}=4$, and $a_{n}+a_{n-1}=4^{n-1}$. It is easy to find that $a_{4}=52$.