On Wed, Feb 20, 2019 at 5:23 PM Willi Egger <context@boede.nl> wrote:

> Hi all,
>
> I am siting with a project of making a “dwarsligger”, you know these
> books, printed on bible-thin-printing paper, which are about  12 x 8 cm.
> One opens them while holding them ‘landscape’ with the spine on the top…
>
> Now there is of course a little struggle with the page numbering. The
> reading page consists out of the even page together with the following
> uneven page. It is easy to print on the uneven page a page number, however
> this will result in uneven page numbers only throughout the book.
>
> My question is, whether there is an algorithm to print page numbers as
> follows:
>
>
> 1  2  3  4  5  6  7  8  9 (this is the ordinary numbering)
> 1     2     3     4     5 (this is the requested numbering)
>
> Does someone have an idea how to solve this?
>
> Any hints are most appreciated!
>
> Pickup n>=0, and find q and  r such
n = 2q + r,    r = 0 or r=1

It's not clear if you have 6 what you want to print (3 or 4 ?)
but playing with that formula can help you .
In many times, it's better to start from zero, so it could be that you
have to translate your input sequence by adding -1
and the output sequence by adding +1 .



>
-- 
luigi