"Busy Beaver Hunters Reach Numbers That Overwhelm Ordinary Math"
The total number of steps that mxdys’ new champion took before halting was greater than 2↑↑↑5, or 2↑↑(2↑↑(2↑↑(2↑↑2))). To unpack this expression, you work outward from the innermost parentheses: 2↑↑2 is 4, and 2↑↑4 is a bit over 65,000. That leaves you with 2↑↑(2↑↑65,000), making the height of the final stack of 2s an incomprehensibly large number. Forget about writing a tower of powers that stretches out for miles or megaparsecs. Even this more compact notation no longer fits in the universe.