How to make so Random Number (under 50 milliseconds) wont repeat twice

I'm making autoclicker and it generates random numbers in milliseconds, let's say it generated delays : 30, 40 , 42 (All < (less than) 50)

Now I want to make it so 4th delay cant be again less than 50, I tried this:

I tried using for loop

        for (int i = 0; i < 4;)
        {

            // Total Delay aka delay1+delay2
            if (totaldelay < 50)
            {
                i++;
            }

            // Should make totaldelay > 50
            if (i == 3)
            {
                delay1 = RandomInt(75, 105);
            }

            // Reset to 0 so it checks from 0 again
            if (total > 50)
            {
                i = 0;
            }





        }