I do find that if you make an excel file with number 1 - (whatever)
Then create a text frame on the master page for the number pages.
If you then go to the main page, and unlink that from the master page (Ctrl Click the frame) the import the list of numbers you made in excel.
You can then thread that text frame by clicking the overset button, go to the next page, and shift click on the frame for the page numbers.
It isn't entirely clear, but are we dealing with one person's contact info per page, or many? Sounds like 1.
If it is, as I mentioned in your other thread, you could set this up as a Data Merge project. Create a two-page template spread, Add whatever you need for the notes page to the left page, and put all of your data fields on the right. You can include a number as one of the fields and palce it anywhere you want. This will only work with one record per page, though.
If you'd rather number pages after the fact, it's probably scriptable to do something with starting a new section every second page and assign the numbers, or you could just add a master frame to the master page and place a number list, which is pretty simple.
None of these techniques is truly automatic in the sense of updating if things are added or deleted, or if pages are rearranged. Any numbering outside the merge whould be done as the last step.