(defun get_s(lst)
 (cond ( (eql lst nil) 0 )
       ( (eql (car lst) 1) (+ 1 (get_s (cdr lst))) )
       ( 1 1)
 )
)

(defun dec_trunc(lst s c)
 (cond ((eql lst nil) nil)
       ((eql s c) (list (- (car lst) 1)) )
       ( 1 (cons (car lst) (dec_trunc (cdr lst) s (+ c 1))) )
 )
)

(defun sum(lst s c)
 (cond ((eql lst nil) 0)
       ((< c s) (+ (car lst) (sum (cdr lst) s (+ c 1)) ))
       ( 1 (sum (cdr lst) s (+ c 1)) )
 )
)


(defun next(lst)
 (setq k (length lst))
 (setq sum_all (sum lst (+ k 1) 1))
 (setq s (- (+ k 1) (get_s (reverse lst))))
 (setq lst (dec_trunc lst s 1))
 (setq sum_now (sum lst (+ (length lst) 1) 1))
 (setq ds (car(last lst)))

 (loop
   ( cond ((eql sum_now sum_all) (return lst)) )
   ( cond ((eql ds 0) (return nil)) )
   ( cond ( (<= (+ sum_now ds) sum_all) (setq lst (append lst (list ds))) (setq sum_now (+ sum_now ds)) )
          ( 1 (setq ds (- ds 1)) )
   )
 )

)

(next '(10))
(next (next '(10)))
(next (next (next '(10))))
(next (next (next (next '(10)))))
(system)