printing 0th index in range in python code example

Example 1: range parameters python

arr_data=[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20] 
user = int(input("Enter the product of numbers: ")) 
for i in range(0,20,1): 
    a = arr_data[i] 
    for t in range(0,20,1): 
        b = arr_data[t] 
        if (a*b) == user: 
            print(a,"x",b,"=",user) 
        else: 
            pass

Example 2: range(n,n) python

# if numbers are same in the range function then,
# the range function outputs empty range
# this is because, there are no integers b/w n and n
for i in range(1,1):
  print("runs")

# prints nothing