##QBIC, 16 bytes
QBIC, 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> QBIC's seen a few updates since this answer was posted. This could now be done with these 12 bytes:
[:|B=B+@*`?B