24 comes next in this run of numbers. This would resemble adding five to a number and then taking two away. This can be deduced from the first three numbers in the sequence: 13 + 5 = 18 and 18 – 2 = 16.
Finding a pattern in a series of numbers makes it possible to predict numbers that appear far later, frequently without recording the complete series. There are further uses for pattern recognition, such calculating probability. Some series of numbers are so typical that they have names. The Fibonacci sequence is one instance where a number is the sum of the two numbers that came before it.