Arithmetic Sequences. An arithmetic sequence is a sequence in which the difference between each consecutive term is constant. An arithmetic sequence can be defined by an explicit formula in which an = d (n - 1) + c, where d is the common difference between consecutive terms, and c = a1.
A geometric sequence is a sequence of numbers in which the ratio between consecutive terms is constant. We can write a formula for the n th term of a geometric sequence in the form. an=arn , where r is the common ratio between successive terms.