The user inputs the start serial number and the number of pages. Then that serial number needs to be printed on top of every page, auto incremental for each page. The final output may be a multipage PDF file. Is it possible to do it with pdfLaTeX? I have been using LaTeX for long but do not know if this requirement can be programmed. As a next step I would like to encode the serial number as a barcode. I think the later requirement will be easier to fulfill.
You can simply define an initial value and add the page number to it. That would look like this, placing the serial number in the top right corner using
EDIT updated the answer to reflect Ulrike Fischer's comments. Also note that this might cause problems if you don't want the serial numbers to increase in the same fashion as the page numbers. For instance, when you number the main matter separately from the front matter.