(comment rank in final pile functions)

(setq base (setq ibase 10.))

(defun r1 (n) n)

(defun r2 (n) (if (divides 2 n) (quotient n 2) (quotient (+ n 13.) 2)))

(defun r3 (n) (cond ((divides 3 n) (quotient n 3))
((divides 3 (add1 n)) (quotient (+ n 13.) 3))
(t (quotient (+ n 26.) 3))))

(defun r4 (n) (cond ((divides 4 n) (quotient n 4))
((divides 4 (add1 n)) (quotient (+ n 13.) 4))
((divides 4 (+ 2 n)) (quotient (+ n 26.) 4))
(t (quotient (+ n 39.) 4))))

(defun divides (m n) (zerop (remainder n m)))