User blog comment:Superiumentarius/Space delimiter sequence/@comment-31607182-20171128182819/@comment-31607182-20171212232537

Just for completeness, I figured out the following approximations:

$$ n|n|1 \approx n^2 \\ n|n|2 \approx n^{2^n}\\ n|n|3 \approx f_3(n)\\ n|n|n \approx f_{\omega}(n)\\ n|n|n|1 \approx f_{\omega+3}(n)\\ n|n|n|2 \approx f_{\omega+6}(n)\\ n|n|n|n \approx f_{\omega + 3n}(n) \approx f_{\omega \cdot 2}(n)\\ n|n|n|n|n \approx f_{\omega \cdot 3}(n)\\ SDS(n) \approx f_{\omega^2}(n)\\ $$

Where SDS(n) refers to n|n|...|n with n n's