Find the rule and fill in the number 12 6 15 31 []]

The first number = 1 ^ 2
The second number = 1 ^ 2 + 1 ^ 2
.
The sixth number = 1 ^ 2 + 1 ^ 2 + 2 ^ 2 + 3 ^ 2 + 4 ^ 2 + 5 ^ 2 = 56
The seventh number = 1 ^ 2 + 1 ^ 2 + 2 ^ 2 + 3 ^ 2 + 4 ^ 2 + 5 ^ 2 + 6 ^ 2 = 92

RELATED INFORMATIONS

1. What should I fill in the question mark part? Why? 8 13 12 6 22 3 43 5 5 3 4 2 9 5 11 6
2. 51 84 99 8 55 13 12 34 this is a regular group of numbers. What should I fill in the question mark?
3. 1. 2, 4, 8, (), () first find the rule, then fill in the number
4. Find the rule 3,6,11, (), 27, (), 51
5. The second grade of primary school is estimated to be 38 + 16 18 + 21 + 27 98_ 51+16
6. 1, 1, 2, 7, 21 what's the next number? A.51 b.52 c.53 d.54
7. Fill in the operation symbol or bracket. 5 = 2
8. 1 / 3 () 1 / 3 () 1 / 3 = 2 / 9 can be filled with brackets and operation symbols
9. In order to make 51 () fill in this number, it has both factor 2 and factor 3. What number can () fill in
10. Please fill in the most likely numbers in brackets: 3,7,21,51103, () Please give the derivation process
11. 38 divided by a number, quotient 27, the remaining 35, find this number
12. 6.15.38.65.106.（）.（） 6.13.27.49.（）.121.（）
13. 1 / 2 1 / 3 1 / 6 1 / 7 () () find the law
14. 2, 3, 6, 11, (), 27, 38
15. Xiaosun bought a whole box of milk from the supermarket. As shown in the picture, there are 12 bags of milk in each box of this specification. The weight of each bag of milk is 250 grams. After careful inspection, he found that the words "net content: 243ml" were printed on the package (1) The density of this kind of milk. (2) when the whole box of milk is placed on the horizontal ground, the contact area between the box and the ground is 0.05m2, what is the pressure of this box of milk on the ground? (two decimal places shall be reserved after the decimal point, regardless of the quality of boxes and bags.)
16. 39 out of 51, 20 out of 90 and 22 out of 44 480ml = () \ \ () l 2750g = () \ \ () kg vs. 4.5 and 19.4 The sum of the numerator and denominator of a minimalist fraction is 9. There are three fractions. Please fill in the brackets below （）\（）＜（）\（）＜（）\（）
17. Find the Rule 13 22 37 52 the next number is
18. What is the number 10 of 7, 13, 22 and 37
19. Fill in the number 20 22 25 30 37 ()
20. 20.22.25.30.37. () what's the rule?