asked 14 years ago
http://en.wikipedia.org/wiki/Knuth's_up-arrow_notation
http://en.wikipedia.org/wiki/Tetration
updated 14 years ago
http://en.wikipedia.org/wiki/Hyperoperation#Examples
http://en.wikipedia.org/wiki/Knuth's_up-arrow_notation#Numeration_systems_based_on_the_hyperoperation_sequence