Step 1: Divide the number into separate digits:
17308 => 1 7 3 0 8
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
1 to 7 = 6
7 to 3 = 4
3 to 0 = 3
0 to 8 = 8
8 to 1 = 7
Step 3: Combine the filters to a string:
6 4 3 8 7 = 64387