Euler's Totient - 1..2500
History:Juan Carlos Ponce Campuzano - Euler's totient function
Wikipedia: Euler's totient function
The first 2500 values of φ(n).
The points on the top line represent φ(p) when p is a prime number, which is p−1.
Script
ϕ = Join({{(1, 1)}, Zip((k, k Product(Zip(1 - 1 / p, p, Unique(PrimeFactors(k))))), k, 2…2500)})