Trying to string.gsub a string to remove adjacent duplicates

Getting Started Newbie Questions
#1

HELP ME PLS…

Im trying to remove adjacent duplicates in a string, the current code I have is not working - 

string.gsub(“baaab”, “(%a)%1+”, “%1”) 

I’m trying to get this to return “bab” not “baaab” or remove any adjacent duplicates in a sting, If I use -

string.gsub(“baaab”, “(%a)%1%1”, “%1”) 

I’ll get “baab”

For some reason I cannot get the “+” to work when referencing a capture am I doing something wrong or is this not possible.

Also the regex that worked on an online regex calculator was (\w)\1+ if it helps. 

Thanks!