User blog comment:B1mb0w/Strong D Function and f epsilon nought (n)/@comment-5529393-20150805104604/@comment-5529393-20150806045817

No, you're missing my point. You can't establish $$D(3^27-3,0,1) >> f_{\varepsilon_0}(3)$$  either, since you still need to use Rule: LN to prove it, and that requires showing $$D(l-1,0,n) = f_\phi^{n-1}(f_\phi(3))$$ for all n.