Step 1: Divide the number into separate digits:
13244 => 1 3 2 4 4
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
1 to 3 = 2
3 to 2 = 1
2 to 4 = 2
4 to 4 = 0
4 to 1 = 3
Step 3: Combine the filters to a string:
2 1 2 0 3 = 21203