After spending a day and half trying to use a stepper motor with the Stepper library, I finally found the solution on a model railroading forum. In the discussion on "Stepper(steps, pin1, pin2, pin3, pin4)" (https://www.arduino.cc/en/Reference/StepperConstructor) there should be a note that the mapping of pins to stepper inputs is pin1 = N1, pin2 = N3, pin3 = N2, and pin4 = N4. It is DEFINITELY not obvious and not easy to find the answer.