Have a look at your list levels, specifically at the item at index 0 on each list. 
The first list may need to be Flattened, so the values for indices line up as expected.
Looks like a list levels issue. You’ve got 3 levels on your x input, but 2 on your y input. So it’s applying the 0001 to all items in the list as that’s the index at the same level. You can either adjust your inputs to match, or be more specific with inputs in designscript (or just use the OOTB ‘+’ node that’s a bit simpler).
Depends on what your intended output is. Many different ways to do it.
thanks
couldt not get i right still on last one, the script u made was helpful but did u have any idea who i wich output this list can have thanks for your answer again
What’s your “A” list input?
If it’s still a 3 level list like in your original post then the same issue I mentioned still applies and you need to either specify the levels you want to work from in your designscript (or ‘+’ node), or modify your input lists so that the levels align (either by flattening the ‘A’ list so they both have 2 levels, or using list.cycle on your ‘B’ list so they both have 3 levels, those 2 methods will have slightly different outcomes, but will give you unique codes regardless).