I honestly don't know if it is the one that the computer came with but we use:
Delta Electronics Inc
Model: ADP-40PH AB
Input: 100-240V~1.2 A 50-60 Hz
Output: 19V 2.1A
The end on it looks about like this one:
https://www.amazon.com/Oneda-Adapter...ds=adp-40ph+AB
Don't know if the above adapter works, but the end is the same.
Hope this helps!