ExE  GoogolTeam/googol GitHub Wiki
ExE, short for the ExtensibleE System, is a notation for large numbers created by Sbiis saibian. this notation has various stages: HyperE Notation (E#), Etended HyperE notation (xE#), CascadingE notation (E^), Extended CascadingE Notation (xE^), and Hyperextended CsacadingE notation (#xE^).
The rules of xE# are shown below:

En = 10^n

@#...#1 = @

@b#...#p (n #s) = @b#...#(n1 #s)b#...#(n #s)(p1)

@b#p = @(@b#(p1))
This calculator also provides the letters A, B, C, and D to change the the first rule, from 10^n to 10*n for B or D, n^10 for C, and n+1 for A. All other rules are the same.
You can also use nonintegers, in which case it will interpolate between the nearest integer cases. (Note that B and D have different interpolations.)