BEAF

Here I'll show about B E A F aka Bowers' Exploding Array Function

Linear Array Notation 

That has a limit of epsilon-zero! (well, even Buchholz Ordinal if you count the array of operator!)

So for 3 entries and below...

{} = 1

{a} = a

{a,b} = a^b

{a,b,c} = a^^^... c ^s ...^^^b

a trailing one can always be deleted.

so {3,4,5} = 3^^^^^4

3 entries gets us upto omega in the fast-growing hierarchy.