Are you just trying to insert a blank cell? If you have:

```
1
2
3
4
5
```

and you want it to be

```
1
2
3
4
5
```

just select (click on) the cell with `2`

in it, right-click, select `Insert...`

, and pick `Shift cells down`

.

**EDIT**

There is also a way to do this using the `IF`

formula, used like so:

```
=IF(logical_test, [value_if_true], [value_if_false])
```

Here are the first 3 cells in the column (assuming we're at the top of column `A`

):

```
A
--------
1 |1
2 |2
3 |=IF(A2=0,A1+1,A2+1)
```

After this, click on cell `A3`

, grab the "handle" in the bottom-right, and drag it down to fill in the rest of your column (or, click on `A3`

, hit `Ctrl``C` to copy the formula, select the cells you want to fill, and hit `Ctrl``V` to paste). You'll then be able to delete any number and the list will continue below it. However, beware adding other data into the deleted cell, as that may interfere with the calculations.