;; Clear and concise
(defun palindromep (lst)
  (equal lst (reverse lst)))

;; Alternative
(defun palindromep (lst)
  (let* ((length-half (floor (length lst) 2))
	 (first-half (subseq lst 0 length-half))
	 (last-half (last lst length-half)))
    (equal first-half (reverse last-half))))

;; C-c C-k
(assert (palindromep '(a b c d c b a)))
(assert (palindromep '(a b c c b a)))
(assert (not (palindromep '(a b c c b b))))
(assert (not (palindromep '(a b c d e))))