This is Fibonacci series, also called golden section series. Take the sum of the first two numbers as the third number and arrange them in turn to form a series.

For example, the above sequence: 1+ 1+2, 1+2=3, 2+3=5, 3+5=8. . . . .

It was first put forward by Italian mathematician Fibonacci in the book "The Book of Algorithms" 1 On Rabbit Reproduction.

Mathematically, Fibonacci series is defined recursively as follows: F0= 1, F 1= 1, fn = f (n-1)+f (n-2) (n >; =2，n∈N*)

/view/8 16.htm This is the encyclopedic link of Fibonacci sequence, which is introduced in detail.