nums.clj

(def nums (take 100 (repeatedly (partial rand-int 10))))

(->> nums
     (map-indexed vector)
     (partition-by second)
     (map (juxt (comp second first) (partial map first)))
     (map (fn [[num indexes]]
             (let [bounds (distinct ((juxt first last) indexes))]
                (str (clojure.string/join "-" bounds) ": " (apply str (repeat num "#"))))))
     (run! println))