The first six terms are:
f(0) = 3
f(1) = 4·f(0) = 4·3 = 12
f(2) = 4·f(1) = 4·12 = 48
f(3) = 4·f(2) = 4·48 = 192
f(4) = 4·f(3) = ?
f(5) = ?
You finish f(4) and f(5). Note that each term is 4 times the previous term, which is what the recursive rule is telling us.