It depends on whether you're entering the sale on Screen 17.1 or 22.

I'm going to presume 17.1, because 22 should automatically recapture it if it's in "prior depreciation."

In the "Sale of Home" section, it should be the second numeric data entry field in the "Business Use" sub-section: "Depreciation allowed after..."

You may need to tweak some other parts of that section.  Keep hitting F1 on any ambiguous checkbox or data entry field and you should get the info you're looking for.