Iterated logarithm

The iterated logarithm, denoted as \( \log^* n \), is a function that represents the number of times the logarithm function must be applied to a number \( n \) before the result is less than or equal to a constant (often 1). In mathematical terms, it can be defined as follows: 1. \( \log^* n = 0 \) if \( n \leq 1 \).