Fibonacci series
noun /ˌfɪbəˈnɑːtʃi sɪəriːz/
/ˌfɪbəˈnɑːtʃi sɪriːz/
(also Fibonacci sequence)
(mathematics)- a series of numbers in which each number is equal to the two numbers before it added together. Starting from 1, the series is 1,1,2,3,5,8,13, etc.