using System.Collections.Generic;

public class Program
{
    public static void Main()
    {
        int outparam;
        Outer.CreateInstance(5);
        outparam = _kList[3];
    }
}

public static class Outer
{
    public static void CreateInstance(int a)
    {
        List<Nested> _kList = new List<Nested>();

        for (int i = 1; i < 10; i++)
        {
            Nested _k = new Nested(a);
            _kList.Add(_k);
        }
    }

    private class Nested
    {
        int a;
        public Nested(int a)
        {
            this.a = a;
        }
    }
}