Press MATH and go to the PRB menu. Enter Data into Lists. It will always be in this order.
Enter n press You should see nCr above the plus key.
Almost every scientific calculator has a built in factorial function. On the example to find 26 choose 17 go to the Home screen of the TI-89. Press eight times to see the y-intercept labeled as a. Using the TI-84 Plus you must enter n insert the command and then enter r.