User blog comment:Cookiefonster/my funktion is faster--grownig/@comment-11227630-20140923105928

$$f_{C(C(...C(\Omega_n,0)...,0),0)}(n)$$ with n nests of C, using Taranovsky's ordinal notation.

In Taranovsky's page he didn't define a fundamental sequence, so here I define one so that it works in FGH:

If $$\alpha$$ is a countable limit ordinal, then the set $$S(\alpha,k)$$ is the set of all ordinals less than $$\alpha$$ and their postfix form has length at most k, then $$\alpha[n]=max(S(\alpha,n))$$.