The tetrofaxul is equal to 200!2 in Hyperfactorial array notation. Tetrofaxul can be thought as "tetrofactorial" of 200, which is, by analogy with expofactorial, means \(f(n) = n \uparrow\uparrow (n-1) \uparrow\uparrow (n-2) \cdots 4 \uparrow\uparrow 3 \uparrow\uparrow 2 \uparrow\uparrow 1\). Thus, tetrofaxul can be represented as \(200 \uparrow\uparrow 199 \uparrow\uparrow 198 \cdots 4 \uparrow\uparrow 3 \uparrow\uparrow 2 \uparrow\uparrow 1\). This is based on tetration. The term was coined by Lawrence Hollom.