Would like to help best I can add is that earlier you typed
The N on a D A P to 210
now you type
The D on a D A P to 210.
which is it?
All I can say is to confirm that the numbers from 1 to 20 do indeed add up to 210.
I think we need angc54 to clarify whether the clue starts with D or N.
The numbers add up to 210 but the digits don't!
Anyway, 'AP to 210' can't be 'add up to 210'