Step 1: Divide the number into separate digits:
76659 => 7 6 6 5 9
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
7 to 6 = 1
6 to 6 = 0
6 to 5 = 1
5 to 9 = 4
9 to 7 = 2
Step 3: Combine the filters to a string:
1 0 1 4 2 = 10142