Comment by iopq

BB(6) could be bigger than Graham's number but we don't even know, that's how big it is

the busy beaver function grows so fast that for some number N it's always going to be larger than any number we can describe in normal math notation

so if you define Graham's number as a function of N like g(N) where Graham's number is g(64), busy beaver still grows faster and for some N it will be bigger