Ok, so here's my first question on Mapleprimes.  

I have the following procedure:

BlocksLSymm:=proc(stringLength) 
local i, j, V;
global vars_set;
V:=Vector(2^(stringLength)+1,symbol=x):
# Create List
vars_set:={};
x[1]:=x[2];
for i from 0 to stringLength do 
 for j from 0 to i do
  vars_set:={op(vars_set), x[2^i-2^j+1]};
 end do; 
end do;
end proc: 

BlocksLSymm(5);

vars_set;