Elegant code & Efficient code

Elegant code & Efficient code, are they inversly proportional?

UM LOL @ PERL FAGS WHO CANT EVEN WRITE THE MOST FUCKING SIMPLE PIECE OF CODE EVER.

(defun primep (n)
  (cond ((= 1 n) 'nil)
    ((= 2 n) t)
    ((evenp n) 'nil)
    (t (let ((limit (floor (sqrt n))))
         (do ((i 3 (incf i 2)))
         ((> i limit) t)
           (if (= 0 (mod n i)) (return-from primep 'nil)))))))

(defun find-largest-prime-divisor (n)
  (if (= n 2) 2
      (do ((i (1+ (floor (sqrt n))) (decf i)))
      ((and (= 0 (mod n i)) (primep i)) i))))

(defun prime-factorize (n)
  (let ((list '()) (factor 1))
    (do ((x n (/ x factor)))
    ((= 1 x))
      (setq factor
        (if (primep x) x
        (find-largest-prime-divisor x))
        list (cons factor list)))
    list))