##[QBIC][1], 16 bytes

 :#*|[1,a|B=B+A?B

Explanation:
 
 : Gets a cmd line param as number called 'a'
 #*| Define A$ as '*'
 [1,a| FOR b = 1 to a
 B=B+A Extend B$ with another astrix
 ?B Print B$
 <FOR LOOP implicitly closed>


 [1]: http://codegolf.stackexchange.com/questions/44680/showcase-your-language-one-vote-at-a-time/86385#86385