Step 1: Divide the number into separate digits:
38804 => 3 8 8 0 4
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
3 to 8 = 5
8 to 8 = 0
8 to 0 = 8
0 to 4 = 4
4 to 3 = 1
Step 3: Combine the filters to a string:
5 0 8 4 1 = 50841