Answer
$1,4,7,10,13$
Work Step by Step
In order to compute the fifth term we will have to plug $n =1,2,3,4,5$ into the given equation.
Now, we have $a_2= a_1+3 = 1+3=4$;
$a_3= 4+3=7$; $a_4= 7+3=10$; $a_5= 10+3=13$;
Thus, we have the terms $1,4,7,10,13$