Pentation

Pentation or quintation refers to the function $$a \uparrow\uparrow\uparrow b$$, where Arrow Notation is used. It produces numbers very much larger than those produced by tetration.

Example 2^^^4 = 2^^2^^2^^2 = 2^^2^^4 = 2^^2^2^2^2 = 2^^2^2^4 = 2^^2^16 = 2^^65536 = 22 2 2 2 : : : : 2       where there are 65536 2's this number is HUGE!

Sunir Shah uses the notation $$a * b$$ to indicate this function. Bowers calls it 'a to the b'th tower'.