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Googology Wiki

Pentacthulhugong is equal to E100,000#^^^#100,000 in Extended Cascading-E Notation.[1] The term was coined by Sbiis Saibian. This number is slightly larger than tethrarxigong.


The 2 parts of the name, "pentacthulhu-" and "-gong", mean E100#^^^#100 (which in turn, means "pentation" and "Cthulhu"), and the function that multiplies the base value by 1,000 respectively.

Approximations in other notations

Notation Approximation
BEAF \(\{X,X,1,2\}\ \&\ 100\,000\) (weaker bound)

\(\{X,X,3\}\ \&\ 100\,000 \) (stronger bound)

Bird's array notation \(\{100000,100000[1[1\neg3]2]2\}\)
Strong array notation \(s(100000,100000\{1\{1`2^{`}\}2\}2)\)
Hyperfactorial array notation \(100000![1(1)2]\)
Fast-growing hierarchy (with this system of fundamental sequences) \(f_{\varphi(1,0,0)}(99999)\)
Hardy hierarchy \(H_{\Gamma_{0}}(100000)\)
Slow-growing hierarchy \(g_{\vartheta(\Omega_2)}(100000)\)


  1. Saibian, Sbiis. 4.3.9 - Extended Cascading-E Numbers Part III. Retrieved 2017-01-13.

See also