The number of columns arranged according to a certain rule is 1,4,7 Then the nth number is I'm going to use it today,

The number of columns arranged according to a certain rule is 1,4,7 Then the nth number is I'm going to use it today,

The answer is 3n-2
Because 1, 4, 7, 10 and. N are arithmetic sequences, we use the general term formula to calculate them directly
an=a1+(n-1)d
Where a1 = 1, d = 3

According to table 1, the natural numbers can be divided into 12345 and 5 rows. For example, 12 is in the fourth column and 3 rows. Then which row and which column is 2000

The third line

Arrange the natural numbers in the following order. In this order, 9 is in the third row and the second column
1 2 4 7 11 16……
3 5 8 12 17……
6 9 13 18……
10 14 19……
15 20……
21 ……
What is the row and column of natural number 2013

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 = 5511 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 20 = 15521 + 22 + 23 + 24 + 25 + 26 + 27 + 28 + 29 + 30 = 255... 55 + 155 + 255 + 355 + 455 + 555 = 18301830 + 61 + 62 + 63 = 201663 the first column is 201662, the second column is 201561, the third column is 201460, and the fourth column is 201

11. Arrange the natural numbers in the order of the right figure: in this arrangement, 9 is in the third row and the second column, then 2006 is in the third row______ Line number______ %
1 2 4 7 11 16
3 5 8 12 17
6 9 13 18
10 14 19
15 20
twenty-one

The number N in the first line is n (n-1) / 2 + 1
The number 63 in the first line is 63 * 62 / 2 + 1 = 1954
The number 64 in line 1 is 64 * 63 / 2 + 1 = 2017
2006-1954=52,64-53=11
2006 ranked No.1__ 53__ Line number__ 11____ %