Step 1: Divide the number into separate digits:
51358 => 5 1 3 5 8
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 1 = 4
1 to 3 = 2
3 to 5 = 2
5 to 8 = 3
8 to 5 = 3
Step 3: Combine the filters to a string:
4 2 2 3 3 = 42233