The A3967 can provide a max of 0.75 amps and your motor requires 1.33 amps. You need an A4988 or DRV8825 stepper driver for that motor.
You wattage calculation for the motor is correct. But something has gone wrong with your power supply calculations. 15W at 24 volts only requires 0.625 amps.
In practice I would probably choose a power supply that could provide about 5 amps just to have a nice surplus. Of course a 10 amp power supply would also be perfectly OK.
Make sure you adjust the stepper driver to limit the motor current to 1.33 amps or the smoke will escape from the motor. And note that most motor and driver specs refer to the current per-coil.