The analysis is as follows:

1, observation series: 1, 1, 2, 4, 7;

2、 1- 1=0; 2- 1= 1; 4-2=2; 7-4=3;

3. Discovery rule: the difference between the first item and the second item is 0, 1, 2, 3 in turn.

4. So the next difference between the first item and the second item is: 4,5,6;

5、7+4= 1 1; 1 1+5= 16; 16+6=22;

6. So, the answer is: 1 1,16,22.

Looking for the meaning of fill-in-the-blank rules

In fact, it is to strengthen the familiarity with the general law of sequence. Although it has many solutions, it is mainly to cultivate your ability to find the general law of series and guess the general term of series (that is, the ability to use incomplete induction), so that when you encounter some series that are not easy to find the general term by general methods, you can guess the general term formula of this series quickly and accurately through the first few terms.

Then prove it by mathematical induction or reduction to absurdity or other methods, bypass the front mountain and get its general formula quickly. Therefore, finding the rules to fill in the blanks will still help us to enhance our understanding of some difficulties and characteristic series.