How to make a forumla go in a pattern rather than in order?

I have numerous data collection points in one Excel sheet and would like to display them all in one column.

For example:
A1=3
A11=4
A21=5

I would like to use a forumla for the following cells to display the above:
B1=3
B2=4
B3=5

I know to use the "=" function but when i drag down the forumla it doesn't follow the pattern of every 10th cell.

Thanks,
Ollie

In B1 try:

=OFFSET($A$1,10*(ROW(B1)-1),0)

And drag down.

Thank you! That worked in my example, however my idea was to manipulate the formula to my actual needs but i failed miserably!
I have attached my example, it is getting all the 'weights' into one column.

I would be extremely grateful if you can take a look, it will save me hours!

Thank you

In cell N3:

=IF(ROW(A1)>COUNTIF($A:$A,"Weight*"),"",INDEX(B:B,SMALL(IF($A$1:$A$10000="Weight (kg)",ROW($A$1:$A$10000)),ROW(A1))))

And in O3:

=IF(ROW(A1)>COUNTIF($A:$A,"Weight*"),"",INDEX(E:E,SMALL(IF($A$1:$A$10000="Weight (kg)",ROW($A$1:$A$10000)),ROW(A1))))

Both of these are array formula and must be entered using Ctrl-Shift-Enter, not just Enter.

Once entered they can be copied down as many rows as required.