Step 1: Divide the number into separate digits:
26000 => 2 6 0 0 0
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
2 to 6 = 4
6 to 0 = 6
0 to 0 = 0
0 to 0 = 0
0 to 2 = 2
Step 3: Combine the filters to a string:
4 6 0 0 2 = 46002