Answer
4, 11, 25, 53
Work Step by Step
The recursion formula tells us what is the next term we are given. we put the $a_{1}$ term for the $a_{n-1}$ to give us $a_{2}$. we can think of it by putting value 2 into n and using the previous term to solve the next one. we can continue to do that to get $a_{3} $ and $ a_{4}$ terms.
example:
$a_{2}=2\times a_{1} +3$
$a_{2}=2 \times 4 +3$
