fibs.clj

; return sequence of first n fibonacci numbers:

(defn fibs [n]
  (case n
    0 '()
    1 '(1)
    2 '(1 1)
    (let [
           x (- n 1)
           y (- n 2)
           z (- n 3)
           s (fibs x)
         ]
      (concat s [(+ (nth s y) (nth s z))])
    )
  )
)

; repl output:
;user=> user=> (= (fibs 3) '(1 1 2))
;true
;user=> (= (fibs 6) '(1 1 2 3 5 8))
;true
;user=> (= (fibs 8) '(1 1 2 3 5 8 13 21))
;true

;---

; 4clojure error:
; (used above function definition with 'fn' rather than 'defn')

; java.security.PrivilegedActionException: java.lang.ClassCastException: clojure.lang.PersistentVector cannot be cast to clojure.lang.MapEntry (NO_SOURCE_FILE:0)