where the an are real numbers. Technically, a sequence is a function whose domain is the set of natural numbers, and whose range is a subset of the real numbers. Sequences may be defined in various ways: By listing, and appealing (via the three dots) to your intuition. Suppose the sequence is 1 2 3 4 5 LO CO 2 ' 5' 10 ' 17' 26' 37' Then the n-th term is an = Explicitly. For example, suppose an = n". Then a1 = a2 - , and a3 = Recursively. For example, the Fibonacci Sequence is defined by a1 = 02 = 1, an+1 = an + an-1, n = 2, 3, 4, .... Thus a3 = a4 , and a5 = Also a sequence may or may not have a limit. For the following sequences, enter the limit, or enter the letter "D" if the sequence diverges. an = n an = n2 + 4n-5 an - (2n-1) (3n-1)