F(f(x))=exp(exp(x)).

[Gottfried]

Note, that the value \(2.46791405115 \) is exactly the value in my picture (recently posted here) of imaginary iteration of \(b^x\) where \( b= \sqrt 2\) and \( f(0)=1 \) is iterated with imaginary height .

Don't you just love the parallel of \(\sqrt{-1} = i\)!

Yeppo !