Is there a database of Property IDs in Travis County available for download?

[Aaron Gough]

I have a list of property addresses and the parcel number in Excel.  I need to add a column for the Property ID.  The only way I know how to get the property ID is to search the assessor or appraisal district website with the address or parcel number, then find the Property ID on that page, then save it.

Is there a downloadable data file will all Property ID's somewhere?
Or, is there some kind of formula I can apply to the parcel number that will give me the Property ID?  I don't know that there is any way to "calculate" the Property ID if I have the parcel number but figured it wouldn't hurt to ask!