From the beginning, what is the number of the thousandth four

From the beginning, what is the number of the thousandth four

Count first
10: There is a 4
10-100: because there is one 4 in 1-10 and nine 1-10 in 10-100,
And there are 10 4's in 40-49
10-100: 1 × 9 + 10 = 19
100-1000: there are 9 hundreds from 100 to 1000, and 19 + 1 4 in a hundred,
And there are 400-499100 4 (only several hundred digit 4)
100～1000 ：20×9 + 100
and so on.
The rule is
10 ：1
10～100 ：1×9 + 10 = 19
100～1000 ：（19+1）×9 + 100 = 280
1000～10000 ：（280+19+1）×9 + 1000 = 3700
.
So the 1000th 4 should be between 1000 and 10000
1000 has 1 + 19 + 280 = 300
Starting from 1000, there are 300 out of 1000, so 1-3000
A total of 900 4, starting from 3000, the 100th 4 is to find the number
There are 20 4 in every 100 numbers, so there are 80 in 3000-3399
And 20, 340034013400234033404 (2), 3405
3406,3407,3408,3409,3410,3411,3412,3413,
3414 (2), 341534163417 (20th)
The number we're looking for is 3417