How about 0-0-0-0-0-0-0-0? Not just one missile sitting in some lonesome silo in North Dakota. The lot of them. For twenty years, before more elaborate safeguards were put in place, punch in eight zeroes and you were away to the races. You see, the idea was they didn't want to slow down the launch process by putting in random numbers to confuse the crews.
It was possible during those early years for the commander of America's Strategic Air Command to launch the whole bloody lot of those ICBMs. From 1957 until 1964, that guy was uber hawk, General Thomas Power.