Good afternoon!

I have a sheet which is keeping track of miscellaneous inventory items. In
Column A, there are several cells with values of even numbers and the cell
directly below that is empty.

What I am trying to achieve is populating the empty cells to have a value of
the cell above it (the even number value cell) plus 1.

In other words, if the value of cell A:2 is 1000, then cell A:3 will be
1001. If the value of cell A:4 is 1200, then cell A:5 will be 1201 and so
forth until the end of the column.

Thank you, in advance, for your help!