I would like to see the formula as well ... I just added the first to the next one and it all went quite logically ... I knew that I had to start with 1 ... then two would be measured with 1 to the same pane and 3 on the other pane ... so I had 1 and 3 ... with those two I could measure three and four so I could not measure five, but since I already could measure four I could use it on the same pane and have 9 on the other pane ... thus having 1, 3 and 9 ... and so on
btw, notice the multiplication by 3