The sequence "6, 12, 18, ..." is an example of an arithmetic sequence, where each number increases by the same amount. In this case, each number is 6 more than the previous one. This pattern continues indefinitely, so after 18, the next number would be 24, followed by 30, and so on. These numbers can also be related to multiples of 6. For instance, 6 is the first multiple, 12 is the second, and 18 is the third. Understanding this sequence helps in various areas of math, such as algebra and number theory, where recognizing patterns is essential.