double-cola kata in Clojure

double-cola.clj

(ns cola.core)

(def names ["Sheldon" "Leonard" "Penny" "Rajesh" "Howard"])

(defn double-size [[size name]]
  [(* 2 size) name])

(def group (map vector (repeat 1) names))

(def groups (lazy-cat group (map double-size groups)))

(defn who_is_next [[[size name] & res] n]
  (cond (<= n size) name
        :else       (recur res (- n size))))

(println (= "Sheldon" (who_is_next groups 1))
         (= "Sheldon" (who_is_next groups 6))
         (= "Penny"   (who_is_next groups 52))
         (= "Leonard" (who_is_next groups 7230702951)))