Purely recursive funtion to fetch nth element of list

nth_element.lisp

(defun elek (lst n)
  (if (= n 0)
      (progn
        (car lst))
      (elek (rest lst) (- n 1))
      )
  )

;; CL-USER> (elek '(1 2 3 4) 2)
;; 3