-- Main> binario 4
-- [1,0,0]

-- Main> binario 5
-- [1,0,1]

-- Main> binario 16
-- [1,0,0,0,0]

-- Main> binario 17
-- [1,0,0,0,1]

bin n =

        if n == 0 then [0]
        else
        if n == 1 then [1]
        else
        (mod n 2):bin (div n 2)

binario n = reverse (bin n)