Step 1: Divide the number into separate digits:
1105 => 1 1 0 5
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
1 to 1 = 0
1 to 0 = 1
0 to 5 = 5
5 to 1 = 4
Step 3: Combine the filters to a string:
0 1 5 4 = 0154