Euler 6.

haskell/euler/6.hs

@@ -0,0 +1,23 @@
+-- The sum of the squares of the first ten natural numbers is,
+-- 1^(2) + 2^(2) + ... + 10^(2) = 385
+
+-- The square of the sum of the first ten natural numbers is,
+-- (1 + 2 + ... + 10)^(2) = 55^(2) = 3025
+
+-- Hence the difference between the sum of the squares of the first
+-- ten natural numbers and the square of the sum is 3025 − 385 = 2640.
+
+-- Find the difference between the sum of the squares of the first one
+-- hundred natural numbers and the square of the sum.
+
+sum_of_squares :: [Integer] -> Integer
+
+sum_of_squares l = sum [ n * n | n <- l ]
+
+square_of_sums :: [Integer] -> Integer
+
+square_of_sums l = (sum l) ^ 2
+
+euler_6 :: [Integer] -> Integer
+
+euler_6 l = square_of_sums l - sum_of_squares l