Gets the number of permutations for alphanumeric ASCII characters in the range of 5 thought 12, totalled.

npr_char.py

import string
# this part is from here: https://www.geeksforgeeks.org/program-to-calculate-the-value-of-npr/
# START Geeksforgeeks snippet
import math 
def fact(n):  
    if (n <= 1): 
        return 1
          
    return n * fact(n - 1)  
  
def nPr(n, r):  
      
    return math.floor(fact(n) /
                fact(n - r))  
# END Geeksforgeeks snippet

choices = string.ascii_letters + string.digits

print('Character choices: '  + choices)
print('-' * 20)
n = len(choices)
rs = range(5, 12, 1)

total = 0

for r in rs:
    x = nPr(n, r)
    print(f'{n} choose {r}: {x}')
    total += x

print('-'*20)
print(f'Total combinations: {total}')

Output for this script:

Character choices: abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789
--------------------
62 choose 5: 776520240
62 choose 6: 44261653680
62 choose 7: 2478652606080
62 choose 8: 136325893334400
62 choose 9: 7361598240057600
62 choose 10: 390164706723052800
62 choose 11: 20288564749598744576
--------------------
Total combinations: 20686229904145969376