I use `lein new app test-println` to create a clojure app and launch the repl with `lein repl`, then I enter `(map println [1 2 3 4 5 6])` and get the expected result:
`test-println.core=> (map println [1 2 3 4 5 6])
1
2
3
4
5
6
(nil nil nil nil nil nil)`

However if I add `(map println [1 2 3 4 5 6])` to the end of `src/test_println/core.clj`:

```
(ns test-println.core
  (:gen-class))

(defn -main
  "I don't do a whole lot ... yet."
  [& args]
  (println "Hello, World!")
  (map println [1 2 3 4 5 6]))

```

`lean run` prints only `Hello, World!`.