diablo.clj

(ns diablo)

(defn craft-cost [x]
  (cond
    (> x 0) (* 100000 (+ 1 x))
    :default 0))

(defn gem-cost [level]
  (reduce +
    (map
      #(*
         (int (Math/pow 3 (- level %)))
         (craft-cost %))
      (range (+ 1 level)))))

;(println (map #(gem-cost %) (range 5)))
;(0 200000 900000 3100000 9800000)