Roman Numerals -- from Wolfram MathWorld
https://mathworld.wolfram.com/RomanNumerals.html
The number of characters in the Roman numerals for 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, ... (i.e., I, II, III, IV, V, VI, VII, VIII, IX, X, ...) are 1, 2, 3, 2, 1, 2, 3, 4, 2, 1, 2, 3, 4, ... (OEIS A006968 ). This leads to a scale-invariant fractal -like stairstep pattern which rises in steps then falls abruptly.
DA: 22 PA: 1 MOZ Rank: 76