you could play all the notes from the D string on the A string by playing 5th fret,
but I personally think it sounds better with the open D note.
the 5-6-7 run at the end is a triplet.
[ Tab from: http://www.guitaretab.com/m/macklemore/380844.html ]
1 . 2 . 3 . 4 . | 1 . 2 . 3 . 4 . | 1 . 2 . 3 . 4 . | 1 . 2 . 3 . 4 . |
e|-----------------|-----------------|-----------------|-------------------|
B|-----------------|-----------------|-----------------|-------------------|
G|-----------------|-----------------|-----------------|-------------------|
D|--------0--------|--------0--0---0-|----------0------|-------------5-6-7-|
A|-----------------|-----------------|-----------------|-------------------|
E|-5-----5---------|---------5-------|-5-----5---------|-------------------|
