1, - 3,5, - 7,9, - 11. According to this rule, what are the 100th and 2009 numbers?

1, - 3,5, - 7,9, - 11. According to this rule, what are the 100th and 2009 numbers?

This is an arithmetic sequence
The general formula is (2n-1) (- 1) ^ (n + 1)
Then the 100th number is - 199
The number of 2009 is 4017

-1, 3, 7, 11. What is the 100th number in this column? Is 20092011 the number in this column? If so, what is the number,
If not, please give reasons

The nth number is 4 * N-5. So the hundredth number is 4 * 100-5 = 395. To see if this number is in the column, is to see if it can be divided by 4 after adding 5. So 2009 is not, 2011 is the 504th number

Find the law, fill in the appropriate number; 1, - 1,3, - 4,5, - 6 Where the 100th number is (the 2009 number is)（

Find the law, fill in the appropriate number; 1, - 1,3, - 4,5, - 6 Where the 100th number is (- 100) and the 2009 number is (2009)
Even numbers are negative, odd numbers are positive,

10 square plus 11 square plus 12 square plus 13 square plus 14 square divided by 365, see if there is a clever way

Let t = 14, the square of 10 to 14 be written as 10 ^ 2 + T ^ 2 + (t-1) ^ 2 + (T-2) ^ 2 + (T-3) ^ 2 = 4T ^ 2-12t + 14 + 100 = 196 × 4-14 × 12 + 14 + 100 = 730
Divide by 365 = 2