Sextintar

Sextintar is equal to \(\underbrace{Tar(Tar(\cdots(Tar)\cdots))}_{6\quad pairs \quad of \quad brackets}=\underbrace{Tar(Tar(\cdots(Tar}_{6\quad Tar's}(6))\cdots))\) = \(f_{\underbrace{C(C(\cdots(C(C(\Omega_{6}2,0),0),\cdots ),0)}_{\text{quintintar}-1)}}(\text{quintintar})\) using the fast-growing hierarchy with fundamental sequences for Taranovsky notation. The term was coined by wiki user Denis Maksudov.

Etymology
The 2 parts of the name, "sexti", "in" and "tar", mean dekotar and Tar function (from Taranovsky's notation) respectively, which form \(Tar(\)\(\text{quintintar}\)\\) when concatenated backwards. So the full name indicates how the number is constructed.