The tethra-ennaelgathor is equal to E100(#^^#)^#^#^#9 in Extended Cascading-E Notation.[1] The term was coined by Sbiis Saibian.


The name of this number is based on the number "tethrathoth" and the number "ennaelgathor".

Approximations in other notations

Notation Approximation
BEAF \(\{100,100(X \uparrow\uparrow X*X^{X^9}) 2\}\)[2]
Bird's array notation \(\{100,100 [1,1,1,1,1,1,1,1,1,2 \backslash 2] 2\}\)
Hyperfactorial array notation \(100![1,[1,[1,1,10],1,1,2],[1],1,2]\)
Fast-growing hierarchy \(f_{\varepsilon_0^{\omega^{\omega^9}}}(100)\)
Hardy hierarchy \(H_{\varepsilon_0^{\varepsilon_0^{\omega^{\omega^9}}}}(100)\)
Slow-growing hierarchy \(g_{\vartheta(\varepsilon_{\Omega2}^{\Omega^{\Omega^8\omega}})}(100)\)


  1. Saibian, Sbiis. 4.3.7 Extended Cascading-E Numbers Part IOne to Infinity. Retrieved 2017-02-15.
  2. Using particular notation \(\{a,b (A) 2\} = A\ \&\ a\) with prime b.

See also

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