The sequence "100100101" is a binary number, which is a system of representing values using only two digits: 0 and 1. In this case, it consists of nine digits, where each position represents a power of 2, starting from the rightmost digit. When converted to decimal, "100100101" equals 293. Binary numbers are commonly used in computing and digital electronics, as they align with the on/off states of electronic switches. This system is fundamental to the operation of computers and is closely related to topics like digital logic and computer programming.