Wikipedia
The McNuggets version of the coin problem was introduced by Henri Picciotto,
who included it in his algebra textbook co-authored with Anita Wah. Picciotto
thought of the application in the 1980s while dining with his son at
McDonald's, working the problem out on a napkin. A McNugget number is
the total number of McDonald's Chicken McNuggets in any number of boxes.
In the United Kingdom, the original boxes (prior to the introduction of
the Happy Meal-sized nugget boxes) were of 6, 9, and 20 nuggets.

Task

Calculate (from 0 up to a limit of 100) the largest non-McNuggets
number (a number n which cannot be expressed with 6x + 9y + 20z = n
where x, y and z are natural numbers).




(defn cart [colls]
  (if (empty? colls)
    '(())
    (for [more (cart (rest colls))
          x (first colls)]
      (cons x more))))
 
(defn nuggets [[n6 n9 n20]] (+ (* 6 n6) (* 9 n9) (* 20 n20)))
 
(let [possible (distinct (map nuggets (cart (map range [18 13 6]))))
      mcmax (apply max (filter (fn [x] (not-any? #{x} possible)) (range 101)))]
  (printf "Maximum non-McNuggets number is %d\n" mcmax))