Shall I get a fitting function by Matlab according to two matrix

Now I have two mat 'X' and 'Y';

And I can get correlation of 'X' and 'Y' by function [R,P]=corrcoef(X,Y); I can do it as below:

X=[1 2 3 4 5 6];

Y=[23 45 56 76 87 98];
[R,P]=corrcoef(X,Y)

R =

      1.0000    0.9927
      0.9927    1.0000

P =

      1.0000    0.0001
      0.0001    1.0000

Then I know the correlation of 'X' and 'Y' is 0.9927 and is very high;

My question is that How I get the function Y=f(X) with correlation of 0.9927?