How to explain...
ƒxb(n)
Let's create a lookup chart for fxb(n)
1(n) = n 1,1(n) = n^1(n) 1,2(n) = 1,1(...(1,1(n) layers ...(n)
2(n) = n^2 n,1(m ) = m^(n(m))^m n,2(n)
n(m) = n^m