Question: For example, I want the first entry in Column B (B1) to show A5, then B2 shows A10, then B3 shows A15.

How would I go about doing this?

Answer: 
For excel you can put this in B1 and drag down

```
=INDEX($A$1:$A$100,5*(ROWS($B$1:B1)-1))

```

To start with A5 instead of A1, use this

```
=INDEX($A$1:$A$100,5*(ROWS($B$1:B1)))

```
Do you want the cell to take the value of A5, A10 etc? or the actual value "A5", "A10". If you want the value from the cells Raystafarian has a good answer. If you want the values "A5" etc use

```
= "A" & 5*rows("$B$1:$B$1)

```