Icosi-hyperillion is equal to H20(20).[1] The name was coined by SuperJedi224. It is comparable to E63#20 in Hyper-E notation.

Approximations

Notation Approximation
Arrow notation \(39\uparrow\uparrow21\)
Hyper-E notation \(E63\#20\)
Fast-growing hierarchy \(f_{3}(20)\)
Hardy hierarchy \(H_{\omega^{3}}(20)\)
Slow-growing hierarchy \(g_{\varepsilon_0}(20)\)

Sources

"-Illion" numbers by SuperJedi224

Level Four

Hyperillion · Exi-hyperillion · Icosi-hyperillion · Cent-hyperillion

Numbers By SuperJedi224

Fibonacci Numbers

Pound-Star Notation

Based on the Faxul

Googovipleccix family

Graham Sequence Numbers

-Illion numbers

Level Four

Hyperillion · Exi-hyperillion · Icosi-hyperillion · Cent-hyperillion

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