Data Validation: Unique combination of number and type from another cell

I have two columns: “D” with type (list with two types: TYPE1 and TYPE2) and “E” in which I will enter numbers.

In my case it is possible to have a row with values in D: “TYPE1” and E: “123” and another row with values in D: “TYPE2” and E: “123” (same number as previous row in column E). I can’t have another row with the same combination of these values.

So for any type, each number can be used only one time in the table.

So, what I want to achieve is to validate the “E” column in order to allow only one combination of type and number !
Can I achieve this with data validation ?

I tried something like this in validation of the E Column but it’s not working:

and((COUNTIF($E1:E20;E1)=1);(D1=type)) where type=the D column range.

Thanks in advance

Thanks. It works !