a = zeros(n-1);
a(1,1) = 2048;
a(1,2) = a(1,1)./8;
a(2,1) = a(1,2);

for i = 2: n-1
    a(i,i)=a(i-1,i-1)./2;
    a(i,i+1)=a(i-1,i)./2;
    a(i+1,i)=a(i,i+1);
end
a(n,n)=a(n-1,n-1)./2;
a