C#-Code

using static System.Console;
using System.Collections.Generic;
using System.Text;

namespace Aufgabe_231
{
    static class Program
    {
        static void Main()
        {
            List<int> result = new List<int>();
            int nmax = (int)1E+4;
            for(var i = 1; i < nmax; i++)
            {
                int[] temp = i.DecToBin();
                if (temp.CheckDoubleNull())
                {
                    result.Add(i);
                    WriteLine($"{i.ToString("n0"),10}: {temp.ToMyString()}");
                }
            }
            WriteLine($"{result.Count.ToString("n0")} items in list");       
            ReadKey();
        }
        static int[] DecToBin(this int n)
        {
            List<int> temp = new List<int>();
            while(n > 0)
            {
                temp.Add(n % 2);
                n /= 2;
            }
            return temp.ToArray();
        }

        static string ToMyString(this int[] n)
        {
            StringBuilder sb = new StringBuilder();
            for (var i = 0; i < n.Length; i++)
                sb.Append($"{n[i],4}");
            return sb.ToString();
        }

        static bool CheckDoubleNull(this int[] n)
        {
            int inull = 0;
            for(var i = 0; i < n.Length; i++)
            {
                if (n[i] == 0)
                    inull++;
                else
                    inull--;
                if (inull == 2)
                    return false;
            }
            return true;
        }
    }
}