Icosacthuloogol

is equal to \(\{100,17[1[2\backslash2\neg2]2]2\}\) in Bird's array notation, using the modified Hierarchical Hyper-Nested Array Notation. The term was coined by googology user .
==Approximations==
Notation 	Approximation
Hyper-Extended Cascading-E Notation 	\(\text{E}100\#\{18\}\#100\)
DeepLineMadom's Array Notation 	\(100[1\{1<2/2>2\}2]17\)
Fast-growing hierarchy (with this system of fundamental sequences)	\(f_{\varphi(16,0,0)}(100)\)
Hardy hierarchy (with this system of fundamental sequences) 	\(H_{\varphi(16,0,0)}(100)\)
Slow-growing hierarchy (with this system of fundamental sequences)	\(g_{\psi_0(\Omega_2^{\Omega_2 16})}(100)\)
==Sources==
Category:Numbers
Category:Numbers by HaydenTheGoogologist2009
Category:Bachmann's collapsing level
Category:Bird's array notation numbers