Question: Can you help me with the program

hello eveyone! sorry, my English is not very good

I writed Neville algorithm

I want to creat a table(or a matrix) Q with

example:

f:=X->2^X;

with value of X: -2,1,0,1,2

-2   1/4

-1    1/2

0    1

1    2

2     4

I want to approximate f at x=0.5 by Neville

then:   for i:=2,...,n   (that case is 5)

             for j:=2,...i

                  Q[i,j]=(x-X[i-j])*Q[i,j-1]-(x-X[i])*Q[i-1,j-1])/(X[i]-X[i-j])

       output(Q)

this is:

-2  1/4     0       0            0          0

-1  1/2     0.875  0           0           0

0  1         1.25   1.3475    0           0

1  2         1.5    1.4375   1.421875  0

2  4         1      1.375      1.40625  1.412109375

do you understand my mind? sorry, my English is not very good

Regards

   sunflower