Question

Find f(5) for this sequence:. f(1) = 2 and f(2) = 4, f(n) = f(1) + f(2) + f(n - 1), for n > 2. f(5) = ______.

Answer 1

Using this equation,
f(n) = f(1) + f(2) + f(n - 1), for n > 2

f(5) = f(1) + f(2) + f(4)
f(4) = f(1) + f(2) + f(3)
f(3) = f(1) + f(2) + f(2)
f(2) = 4
f(1) = 2

f(3) = 2 + 4 + 4 = 10
f(4) = 2 + 4 + 10 = 16
f(5) = 2 + 4 + 16 = 22

So, f(5) = 22