Функция: разложить целое число k на целые числа a и b так, чтобы k=3a+5b

(defun task (k)
(setq a 0)
(setq b 0)
(do (
(a(+ a 1))
(b(+ b 1)))
((=k(+(* a 3)(* b 5)))(print a) (print b))))

(defun k-sums (k n m)
  (loop for a in (row k n)
        nconc (loop for b in (row k m)
                    when (= (+ a b) k)
                    collect (list (/ a n) (/ b m)))))
 
(defun row (k n)
  (loop for e from 0 to (truncate k n)
        collect (* e n)))
 
> (k-sums 234 3 5)
((3 45) (8 42) (13 39) (18 36) (23 33) (28 30) (33 27) (38 24) (43 21) (48 18)
 (53 15) (58 12) (63 9) (68 6) (73 3) (78 0))

(defun k-sums (k n m)
  (loop for a in (row k n)
        nconc (loop for b in (row k m)
                    when (= (+ a b) k)
                    collect `(,(/ a n) ,(/ b m)))))
 
(defun row (k n)
  (loop for e upto (truncate k n)
        collect (* e n)))
 
> (k-sums 234 3 5)
((3 45) (8 42) (13 39) (18 36) (23 33) (28 30) (33 27) (38 24) (43 21) (48 18)
 (53 15) (58 12) (63 9) (68 6) (73 3) (78 0))

(defun decomp (k a b)
 (let ((r nil))
  (iter (for i from 0 to (\ k a))
     (iter (for j from 0 to (\ k b)) 
           (when (= k (+ (* i a) (* j b))) (collecting (list i j) into r)))) r))
 
==> DECOMP
 
(decomp 16 3 5)
==> ((2 2))
 
(decomp 65 3 5)
==> ((0 13) (5 10) (10 7) (15 4) (20 1))