for N=2:60

    D1=DM1(N); D2=D1*D1; 
   
    ss=D1(N+1,1)*D1(1,N+1)-D1(1,1)*D1(N+1,N+1);

    for j=1:N-1
      al1=(D1(1,N+1)*D1(N+1,j+1)-D1(N+1,N+1)*D1(1,j+1))/ss;
      al2=(D1(N+1,1)*D1(1,j+1)-D1(1,1)*D1(N+1,j+1))/ss;

        for i=1:N-1
          A(i,j)=D2(i+1,j+1)-D2(i+1,1)*al1-D2(i+1,N+1)*al2;
        end
    end

    bb=abs(eig(A));
    aa=max(bb);

    cc=aa;
    for j=1:N-1
    if bb(j) < cc & bb(j) >0.000001
       cc=bb(j);
    end
    end

    xx(N-1)=N;
    err(N-1)=aa/(N^4);
    grr(N-1)=cc;

end

    semilogy (xx, frr)