Answer
$a_1=3 \\ a_2=1 \\ a_3=3 \\ a_4=1 \\ a_5=3$
Work Step by Step
We are given that $a_n=4-a_{n-1}$ and $a_1=3$. In order to determine the remaining values, we will have to substitute $n=2,3,4,5$ into the given sequence:
$a_2=4-a_1=4-3=1 \\ a_3=4-a_2=4-1=3 \\ a_4=4-a_3=4-3=1 \\ a_5=4-a_4=4-1=3$