sum-of-squares.clj

(defn sum [coll]
  (apply + coll))

(defn squares [coll]
  (map #(* % %) coll))

(def first-n take)

(defn integers []
  (iterate inc 1))

(defn sum-of-squares-of-first-n-integers [n]
  (sum (squares (first-n n (integers)))))

; so...
(sum-of-squares-of-first-n-integers 100)

; ... or...
(sum (squares (first-n n (integers))))