Step 1: Divide the number into separate digits:
29549 => 2 9 5 4 9
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
2 to 9 => 7
9 to 5 => 4
5 to 4 => 1
4 to 9 => 5
9 to 2 => 7
Step 3: Convert distances to codes (0=E[qual],
1 & 9 = C[onsecutive], 2-8 = N[one]):
7 => N
4 => N
1 => C
5 => N
7 => N
Step 4: Combine the filters to a string:
N N C N N = NNCNN