An arithmetic progression (AP) is a sequence of numbers in which the difference between consecutive terms is constant. This difference is called the common difference. For example, in the sequence 2, 5, 8, 11, the common difference is 3, as each term increases by 3. The general formula for the nth term of an arithmetic progression is given by a_n = a_1 + (n-1)d , where a_1 is the first term, d is the common difference, and n is the term number. Arithmetic progressions are widely used in various fields, including mathematics, finance, and computer science.