4.12.24.40. 4.12.24.40. What is this kind of number expressed by an algebraic expression? For example, 1.3.5.7.9 can be expressed as 2N-1

The first: 4, the second: 12, the third: 24, the fourth: 40, the first is 1 + 1 + 1 + 1, n-connected + 4 times, the second is 2 + 2 + 2 + 2 + 2, n-connected + 6 times, and so on, the third is n-connected + 8 times, so 24 is connected + some times. The first is connected 4, the second is connected 6, and the third is connected 8, from which we can get: the number of land n is: (2n + 2) n

RELATED INFORMATIONS

1. Find the rule: () () () 40 24 16 12 () ()
2. 2. 4, 7, 12, 21, 38, 71, (), 265 what do you fill in the brackets?
3. Observe the sequence 6, 7, 9, 13, 21, then fill in the rule on the horizontal line (that is, the next number)
4. Finding the law of sequence 2 2 4 6 8 find the law, why, please specify
5. What's the rule of 5 4 12 17.5 24 sequence! Find the last five numbers. Find the average of the last 10 numbers I don't know the rules of these five numbers!
6. How to answer 5.17.21.25
7. 2. 5, 10, 17, 26, 37, 50. What is the 100th number of the sequence
8. Find sequence 1 / 2, 3 / 4, 5 / 8, 16 / 17 The sum of the first n terms of 2N-1 / 2 ^ n A problem in the summation of sequence
9. The first n terms and Sn of sequence 3 / 2,5 / 4,9 / 8,17 / 16, ·· (2 ^ n) + 1 / 2 ^ n It seems that we are going to use some kind of dislocation subtraction
10. 14, 15, 16, 17, 21, 20, 19, 18, 22, 23, 24, 25, when the row reaches 200, in which row, in which column? When the row reaches 3211? 22,23,24,25, 29, 28, 27, 26 go on
11. Fill in the numbers 4,12,24,40, ()
12. Find the sequence of 1 × 2 / 6, 2 × 3 / 6, 3 × 4 / 6 The sum of the first n terms of n × n + 1 / 6
13. Sequence 1, a ^ 2, a ^ 3 The sum of the first n terms of a ^ (n-1)
14. Sequence 1, - A, a ^ 2, - A ^ 3 The sum of the first n items of is
15. Sequence 1 + 1 / (1 * 2) + 1 / (2 * 3) + ··· + 1 / (99 + 100)= 1/(99*100)
16. In the sequence 1 / 2,1 / 3,2 / 3,1 / 4,2 / 4,3 / 4,1 / 5 What is 78 / 99? Find the sum of the first 100 items
17. Sequence 1. - 2,3, - 4 ,99,-100,… What are the top 200 items and?
18. Sequence 1 / 1,1 / 2,2 / 1,1 / 3,2 / 2,3 / 1,1 / 4,2 / 3,2 / 3,4 / 1 Item 2003 The teacher's answer is 50 / 14. I made 50 / 13 myself. Please come and see how much it is,
19. Is the sum of the first n items of sequence 1 - A ^ 2 - A ^ 3? Sequence 1 - A ^ 2 - A ^ 3 What is the sum of the first n items?
20. There is a sequence: 1 / 1,2 / 1,1 / 2,3 / 1,2 / 2,1 / 3,4 / 1,3 / 2,2 / 3,1 / 4 What is the column 7 / 19?