A recursion formula and the initial term$($s$)$ of a sequence are given. Write out the first five terms of the sequence.

$a_1=4,a_{n+1}=-a_n$

$4,-4,4,-4,4$

$4,0,-4,-8,-12$

$4,-16,64,-256,1024$

$-4,4,-4,4,-4$