The following instructions should give you what you require:
1. First you must create a Custom Format and then apply it to all the Cells that will display the date format you require:
- Highlight the desired Column where the date format is to be displayed, right-click the highlighted column and select 'Format Cells'
- In the 'Category' window select 'Custom'
- in the 'Type' window bar enter
ddd-dd
then select 'OK'
- The custom format is now applied to all the selected column cells
2. Next you need to place a start date somewhere on the spreadsheet, suggest you place it the first cell of the Column you just formatted e.g. 11/2/13 or 11/02/2013, either will do. This should then display as Mon-11.
3. Now for the exciting part!
- In the next Cell directly below the date you just entered type in this formula:
=INDIRECT(ADDRESS(ROW()-1,COLUMN()))+1
(Note that this formula references the Cell directly above and then increments that value by 1)
4. Now as if by Magic, you should see the next Day Name and Date number sequence as Tue-12
5. To finish, all you need to do now is copy the Cell that you just put the formula into and then Paste it into the Cells that follow-on down the column!
Another option available to go with the above, instead of placing the initial start Date into the first cell as done at step 2, you could place the date anywhere on the spreadsheet and then use that cell reference. e.g =A2 where A2 has the text 11/2/13
Hope this is what you were looking to do and it works ok for you.