Project Euler Problem 6

Problem6.clj

;;; 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.
(defn calc-diffs [seq]
  (let [square-sum (reduce + (map #(* % %) seq))
        sum (reduce + seq)
        sum-square (* sum sum)]
    (- sum-square square-sum)))

(calc-diffs (take 10 (iterate inc 1)))
;;;=>2640
(calc-diffs (take 100 (iterate inc 1)))
;;;=>