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).




0 temp put
100 6 / times
  [ i 6 * 
    100 9 / times
      [ dup i 9 * +
        100 20 / times
          [ dup i 20 * +
            dup 101 < if
              [ dup bit
                temp take | temp put ]
            drop ] 
        drop ] 
    drop ]
-1 temp take
101 times
  [ dup i bit & 0 =
    if 
      [ nip i swap
        conclude ] ]
drop dup 0 < iff
  [ drop 
    say "There are no non-McNugget numbers below 101" ]
else
  [ say "The largest non-McNugget number below 101 is "
    echo ]
char . emit