Hard Riddle

since newy won the last one i will do a hard riddle for a prize. winner will get a no lag shirt and an umbrella. srry but those r the only things i have alot of. if i get more american flags or something ill use those in the contests. Plz no cheating. here it is. What row of numbers comes next in this series?

1
11
21
1211
111221
312211
13112221