Which modifier added to a 1D20 has the closest outcome probability as rolling 2D20 with advantage with no modifier?

I’m trying to determine the probability of every modifier to a 1D20:

1D20 +1 1D20 +2 1D20 +3 1D20 +4 1D20 +5 

vs flat 2D20s with advantage

2D20 (Keep highest) 3D20 (Keep highest) 4D20 (Keep highest) 

Any help would be highly appreciated