Mark a cell adjecent to another cell baced on a lokkup

Column A is a list of unique numbers
I want to look in Column A based on the contents of Cell D2 (The value in D2 changes with each lookup)
When a match is found in Column A I want to change the cell background color to Green
The Cell found in A that matches D2 needs to remain green with successive lookups
Eventually all cells may be Green, those that are not, are not found

Any help would be greatly appreciated.