Need AppleScript Math Help

I need to create a program in AppleScript to find the highest number that CANNOT be obtained by adding 7's and 3's together by only using addition.

Any help would be appreciated.

well with a little math you can do most of it by yourself, and then see what your looking for

first you can see that anything past 12 can be made with 7 and 3's, 12=3+3+3+3, 13=7+3+3, 14=7+7, anything higher then that can be made by adding 3 to one of those numbers, so your really only checking for those number under 12, and there are not too many, its just these

1,2,4,5,8,11

so the i guess its probably easiest to check if its 12 or over, if its less then check if its any of the above numbers that cannot be created with just 7's and 3's