Print the tribonacci numbers

tribonacci.cpp

#include <iostream>

// See https://arxiv.org/abs/2404.01483

long p(long x, long y, long z)
{
  return x*x*x + 2*x*x*y + x*x*z + 2*x*y*y - 2*x*y*z - x*z*z + 2*y*y*y - 2*y*z*z + z*z*z;
}

const int N = 505;

int main()
{
  for (long x = 1; x < N; ++x)
  {
    for (long y = x + 1; y < N; ++y)
    {
      for (long z = y + 1; z < N; ++z)
      {
        if (p(x, y, z) == 1)
        {
          std::cout << x << ' ' << y << ' ' << z << std::endl;
        }
      }
    }
  }
}