Answer
$a_n=3n-2$
Work Step by Step
Our aim is to determine a formula for the general term of the arithmetic sequence $a_n$.
Such as: $a_n=a_1+(n-1)d$
we have $a_2-a_6=a_1+d+a_1+5d$
or, $4-16=a_1+d+a_1+5d$
or, $d=3$
Thus, $a_1=4-d=4-3=1$
Now, $a_n=a_1+(n-1)d \implies 1+3n-3$
or, $a_n=3n-2$
