UID for each form

What is the problem? Please be detailed.
Is it possible to create a serial number within a form to create a Unique serial number for the form being filled out? This should be self generating and there should not be user interaction.

What ODK tool and version are you using? And on what device and operating system version?
XLS form 1.4.7

What steps can we take to reproduce the problem?
Create a simple form, submit multiple times. I need each form to have a serialized number similar to n+1

What you have you tried to fix the problem?
Searched ODK pages and XLS form pages for reference

Anything else we should know or have? If you have a test form or screenshots or logs, attach here.
This can be any form. I am attempting to add function to a form to create a serial number that can be printed out per record and can also be queried.

In an offline data collection system, you cannot have both a unique ID and an ID that increments in the way you've described. See Add auto generate unique serial number - #3 by yanokwa for some options.