Vigintation refers to the 20th hyperoperation starting from addition. It is equal to \(a \uparrow^{18} b\), using Knuth's up-arrow notation.[1]

Vigintation can be written in array notation as \(\{a,b,18\}\), in chained arrow notation as \(a \rightarrow b \rightarrow 18\) and in Hyper-E notation as E(a)1#1#1#1...1#1#1#b (17 ones).

Vigintational growth rate is equivalent to \(f_{19}(n)\) in the fast-growing hierarchy.


See also

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