This is reply to the post: http://excelexperts.com/add-incremental-numbers

Having your column filtered, you probably insert incremental numbers in different column, right?
1. Filter your data by column A
2. Enter the first value in column B, for example: 100
2. Select the remaining cells in column B to be filled
3. Press F5 and choose "Special", select "Visible Cells Only"
4. In the first empty cell in column B type = (select cell with 100 entered ) + 1
5. Press CTRL+ENTER

You will get 100, 101, 102 etc. in column B, only in visible rows.

Screenshot attached.