{- Binomial coefficient and Pascal's triangle example, by Travis Veralrud
   CSE 341, Autumn 2008 -}

-- function for calculating n! (n factorial)
factorial:: Integer -> Integer
factorial 0 = 1
factorial n = n * factorial (n-1)

-- returns a list of coefficients for function (1+x)^n, given n
binoms:: Integer -> [Integer]
binoms n = [ (factorial n) `div` (factorial k * factorial (n-k)) | k <- [0..n] ]

-- an infinite list containing the rows of Pascal's triangle.
pascals_triangle = map binoms [0..]