If you would like to find f(5), you can calculate this using the following steps:
f(1) = 4
f(n) = f(n-1) + 3 n
f(2) = f(2-1) + 3 2 = f(1) + 6 = 4 + 6 = 10
f(3) = f(3-1) + 3 3 = f(2) + 9 = 10 + 9 = 19
f(4) = f(4-1) + 3 4 = f(3) + 12 = 19 + 12 = 31
f(5) = f(5-1) + 3 * 5 = f(4) + 15 = 31 + 15 = 46
The correct result would be [4] 46.
