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).




mcnugget: procedure options(main);
    declare nugget(0:100) bit, (a, b, c) fixed;    
    do a=0 to 100; nugget(a) = '0'b; end;
 
    do a=0 to 100 by 6;
        do b=a to 100 by 9;
            do c=b to 100 by 20;
                nugget(c) = '1'b;
            end;
        end;
    end;
 
    do a=100 to 0 by -1;
        if ^nugget(a) then do;
            put skip list('Maximum non-McNuggets number:', a);
            stop;
        end;
    end;
end mcnugget;