![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
There is a number string: 1.4.7.10.13.16.19.22.25 Is natural number 2005 in this string? If it is, which number is it? If not, please explain the reason
The former number is three less than the latter
Then the general term an = 3n-2
If 2005 is one of them
3n-2=2005
3n=2007
n=900
N is a positive integer
So 2005 is the 900th in this series
RELATED INFORMATIONS
- 1. Among the 13 numbers 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34 and 37, at least how many numbers can be taken out to ensure that there are many numbers in them The sum of the numbers is 38? And explain the reason
- 2. There is a string of numbers: 1,4,7,10,13,16,19,22,25 '. Please calculate the sum of the first 100 numbers of this string
- 3. There are a series of numbers: 1,4,7,10,13,16,19,22,25,,,, help There are a series of numbers: 1,4,7,10,13,16,19,22,25 (1) Calculate the sum of the first 100 numbers (2) Is 2005 in here? Why?
- 4. The number of a column is grouped as follows: (1), (4,7), (10,13,16), (19,22,25,28) What's the row and position of 2005?
- 5. Calculate 1 × 4 + 4 × 7 + 7 × 10 +... + 19 × 22 + 22 × 25
- 6. 1 * 1 / 4 + 4 * 1 / 7 + 7 * 1 / 10 + 10 * 1 / 13 + 13 * 1 / 16 + 16 * 1 / 19 + 19 * 1 / 22?
- 7. Calculation: 1 / 1 × 4 + 1 / 4 × 7 + 1 / 7 × 10 + 1 / 10 × 13 + 1 / 13 × 16 + 1 / 16 × 19 + 1 / 19 × 22 =?
- 8. From 1 to 9, fill in the following formula () + () = (), () - () = (), () + ()=（ From 1 to 9, the number can not be repeated, each number can only appear once, fill in the following formula () + () = (), () - () = (), () + ()=（
- 9. (a+b)(a2_ ab+b2).
- 10. If lgx + lgY = 2, then the minimum value of X + y is______ ．
- 11. Divide 19,20,21,22 into 24 by "+. -. *"——
- 12. 21, 26, 19, 24, (), (), 15, 20 what do you fill in the brackets?
- 13. There is a set of numbers: 1, 6, 7, 12, 13, 18, 19, 24 If you write down according to this rule, the number at position 20 is () Like the title,
- 14. According to the rule, fill in the appropriate number in (), a.1/1, 7 / 8, 5 / 6, 13 / 16, 4 / 5, 19 / 24, (), B, 1 / 3, 1 / 2, 5 / 9, 7 / 12, 3 / 5, 11 / 18, ()
- 15. Help to find the rule 2, 3, 5, 9, 19. What's the next number 2, 3, 5, 9, 19. What's the next number
- 16. Find the rules: 7 in the first line, 19 in the second line, 37 in the third line, how many in the sixth line, and how many in the nth line
- 17. (Mathematics) find the law 5,6,19,17, (), - 55, in which 344 is filled in brackets. How do you calculate it It is to find out the law of 5,6,19,17344, - 55
- 18. Fill in 1.1, 1, 2, 3, 5, 8, (), 21, 34, 55, 2.190, 94, 46, 22, (), ()
- 19. What should I fill in after 1 22 2 44 3 55
- 20. Fill in the blanks 1, 22, 2, 44, 3, 55, (), () Why?