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).




int N, A(101), X, Y, Z;
[for N:= 0 to 100 do A(N):= false;
for X:= 0 to 100/6 do
    for Y:= 0 to 100/9 do
        for Z:= 0 to 100/20 do
            [N:= 6*X + 9*Y + 20*Z;
            if N <= 100 then A(N):= true;
            ];
for N:= 100 downto 0 do
    if A(N) = false then
        [IntOut(0, N);
        exit;
        ];
]