want to index as shown in figure

HELLO, WANT THIS TYPE OF INDEXING.... THANKS IN ADV

clc
clear all
close all
N=7;
b=0.003;
R=2;
hmin=0.02e-3;
x=linspace(-b/2, b/2, N);
delx= x(2)-x(1);
display(x);
for I=1:N
H(I)=hmin+(x(I)^2)/(2*R);
end
for I=2:N-1
Z(I)=(((H(I+1)+H(I))*0.5)^3)+(((H(I)+H(I-1))*0.5)^3);
A(I)=1;
B(I)=-((((H(I)+H(I-1))*0.5)^3)/(Z(I)));
C(I)=-((((H(I+1)+H(I))*0.5)^3)/(Z(I)));
D(I)=-(2.6527e-004*(H(I+1)-H(I-1)))/(Z(I));
end
A2=[A(2:N-1)];
B2=[B(3:N-1)];
C2=[C(2:N-2)];
X=diag(A2)+diag(C2,1)+diag(B2,-1);
P1=4e6;
P2=0;
D2=[D(2:N-1)];
Y=[D(2)-(B(2)*P1);D(3);D(4);D(5);D(N-1)-(C(N-1)*P2)];
P = (inv(X))*Y;
display(P);
P3=[P(2:N-1)];
display(P3);
Z=[P1;P(2:N-1);P2];
plot(x,Z);