Answer
A(n) = A(n - 1) + 1 ; A(1) = 4
Work Step by Step
The formula for a recursive expression is A(n) = (n - 1) + c (c represents the common difference)
All of the missing pieces in this equation are provided in the explicit equation in the question where the c value is the d value in the explicit equation and A(1) is listed before (n - 1).
C = 1
A(1) = 4
After we plug this in the explicit expression, we get the formula A(n) = A(n - 1) 1 ; A(1) = 4