Write code to match a specific Big-O-Notation

Our class was challenged by a professor at uni that if we were able to find a algorithm that fittingly describes the following Big-O-Notation, we'd instantly pass his class. I wanted to ask if any of you know how this could be done since I've been struggling to make it work without just simplifying it. (Could be any language, i chose c++ for my example)


O(4n · (-2 + 3n) · (n - log(n)) / n) = ?




Simplifying it often gave me either O(n^2) or O(n^3) which would be easy enough to implement but i feel like is not the goal of the challenge.
I've tried directly changing each part into algorithm logic like this:
#include
#include

void Algorithm(int n) {
for (int i = 1; i