EulerPhi

EulerPhi[n] gives the Euler totient function ϕ(n), which counts integers up to n that are coprime to n.

Examples

Count integers coprime to 12:

EulerPhi[12]
(* 4 *)

Totient values for first 10 integers:

Table[EulerPhi[n], {n, 1, 10}]
(* {1, 1, 2, 2, 4, 2, 6, 4, 6, 4} *)

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