Fibonacci task

Fib.hs

-- file: Fib.hs
-- Task: Generate first n Fibonacci numbers, then sum it

-- fib: given n for the index of the Fibonacci series, return the corresponding value, e.g. fib 9 gives 34
fib :: Int -> Int 

fib 0 = 0 
fib 1 = 1 
fib n = fib (n-1) + fib (n-2)

-- fib_n: given n for 0..n as the indexes of the Fibonacci series, return the values
fib_n :: Int -> [Int]

fib_n 0 = []
fib_n n = fib_n (n - 1) ++ [fib n]

-- task completion: sum (fib_n n)