I know how to solve Recurrence Relation problems, I just need help writing up the equation:

Assume that the deer population of Rustic County is 200 at timen = 0 and 220 at time n = 1 and that the increase from time n-1 to time n is twice the increase from time n-2 to time n-1. Write a recurrence relation and an initial condition that de ne the deer population at time n and then solve the recurrence relation.