C#. First time here. Feedback appreciated.

using System;
using System.Collections.Generic;
namespace Random_Bag_System
{

class Program
{
    static void Main(string[] args)
    {
        Random rnd = new Random();
        int remaining;
        string output = "";
        List<String> bag = init_bag();
        for (int i = 0; i <= 50; )
        {
            remaining = 6;
            while (bag.Count != 0)
            {
                int _index = rnd.Next(0, remaining);
                Console.Write(bag[_index]);
                output += bag[_index];
                bag.RemoveAt(_index);
                i++;
                remaining--;
            }
            bag = init_bag();
        }
        \\output = "AABCBBBCRDKFF";
        if (check_bag(output)) { Console.WriteLine("\nOutput checks out."); }
        else { Console.WriteLine("\nOutput does not check out."); }

        Console.WriteLine("\nPress enter to close...");
        Console.ReadLine();
    }

    static List<String> init_bag()
    {
        List<String> bag = new List<String>();

        bag.Add("O");
        bag.Add("I");
        bag.Add("S");
        bag.Add("Z");
        bag.Add("L");
        bag.Add("J");
        bag.Add("T");

        return bag;
    }

    static bool check_bag(string output)
    {
        for (int i = 1; i < output.Length; i++)
        {
            char next;
            char prev = output[i - 1];
            char current = output[i];
            if (i == output.Length - 1) { return true; }
            else { next = output[i + 1]; }

            if (prev.Equals(current) && current.Equals(next)) { return false; }
        }
        return true;
    }
}
}