The tethriterhecate (also called tethritera-by-hyperion) is equal to E100#^^#>#*#100 using Extended Cascading-E Notation.[1] The term was coined by Sbiis Saibian.


The name "tethriterhecate" comes from the suffix "-hecate" and the number tethriterator.

The name "tethritera-by-hyperion" comes from the word "hyperion", the number tethriterator and the -by- infix, which indicates expression multiplication.

Approximations in other notations

Notation Approximation
BEAF \(\{100,100(X \uparrow\uparrow (X^2)) 100\}\)
Bird's array notation \(\{100,100[1 \backslash 1,2]100\}\)
Fast-growing hierarchy \(f_{\varepsilon_{\omega}{99}}(100)\)
Hardy hierarchy \(H_{\varepsilon_{\omega}^{99}}(100)\)
Slow-growing hierarchy \(g_{\vartheta(\varepsilon_{\Omega^2} {98} + \varepsilon_{\Omega \omega})}(100)\)


  1. Saibian, Sbiis. 4.3.7 Extended Cascading-E Numbers Part IOne to Infinity. Retrieved 2017-01-02.