These are the equations which defines a so large Large number. I think it is larger than 10^100 or Graham number.

Here is the detail. https://googology.wikia.org/ja/wiki/%E3%83%A6%E3%83%BC%E3%82%B6%E3%83%BC%E3%83%96%E3%83%AD%E3%82%B0:Koteitan/%E7%9C%9FEB%E6%95%B0%E5%88%97%E3%82%B7%E3%82%B9%E3%83%86%E3%83%A0

Here is the estimation of the size (Japanese). https://docs.google.com/spreadsheets/d/19JJDBhjbCf2nczXFrUYcqHDUlsMZS5c5moTaRomCFo8/edit#gid=0