A sequence is a 
            set of numbers in a specified order. It is normally defined by some 
            rule so that a formula can be given for a typical member of the sequence.
					
					For example,
                    5, 8, 11, 14, 17, ..., 3n + 2
                    6, 9, 14, 21, 30, ..., n2 + 5,... when n is a natural number.