combos.py

import itertools
import string


def main():
    alphabet = string.ascii_lowercase

    for r in range(2, 6):
        perms = len(list(itertools.permutations(alphabet, r)))
        perms_with_reps = len(list(itertools.product(alphabet, repeat=r)))
        combos = perms_with_reps - perms

        # x= r(26*(n-1)) +r
        ryan_x = (r * (26 * 25)) + r
        print r, perms, perms_with_reps, combos, ryan_x

if __name__ == '__main__':
    main()

'''
[amckinley src]$ python combos.py
2 650 676 26 1302
3 15600 17576 1976 1953
4 358800 456976 98176 2604
5 7893600 11881376 3987776 3255
'''