I don't think you are allowed to do it.

Form 3115 is used for a "change" in accounting method, and the 'catching up' on depreciation is usually allowed because you go from an "impermissible method" (not claiming depreciation) to a "permissible" method (claiming depreciation).

If it was not rented in 2018, depreciation is not "permissible" in 2018, so there is no "change" to use Form 3115 for.

There is a slightly more lenient rule in the year of the sale, but I still don't think it will be allowed for the same reason I explained above.

As a side note:  Whenever the property is sold, there will be "Nonqualified Use" for purposes of the $250,000/$500,000 exclusion.  That prorates the allowed exclusion.

Although the $250,000/$500,000 exclusion does not apply to depreciation that was taken, it CAN be applied for depreciation that was never actually taken.  So the unclaimed depreciation will still lower the Basis of the home, but part of the might be canceled out by the prorated $250,000/$500,000 exclusion.