为什么这会将10加到List C＃中的所有元素？

Hi hello I'm new to C# and I was just wondering why this prints a 1 before all the elements in my list.

using System.Collections.Generic;

namespace HelloWorld
{
    class Program
    {
        static void Main(string[] args)
        {
            List<int> primes = new List<int> { 4, 5, 6 };
            for (int i = 0; i < primes.Count; i++)
            {
                int prime = primes[i];
                Console.WriteLine(prime + '\n');
            }
        }
    }
}