namespace WindowsFormsApplication1 {
    public partial class Form1 : Form {
        int i;
        public Form1() : this(1) { }
        public Form1(int i) {
            this.i = i;
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e) {
            this.Text = i.ToString();
            if (i < 5) {
                Form1 form = new Form1(i + 1);
                form.Show();
            }
        }
    }
}