data ACF; A=(.8+.1/.28)/1.7; file print; put "A is " A;
  do h=0 to 10;
  rho_h = A*(.9)**h+(1-A)*(-.8)**h;
  yule = 0.1*yule1+0.72*yule2;
  if h=0 then yule=1; if h=1 then yule=.1/.28;
  output; yule2=yule1; yule1=yule; end;
proc print;
run;

A is 0.6806722689


      OBS       A        H     RHO_H       YULE      YULE1      YULE2

        1    0.68067     0    1.00000    1.00000     .          .
        2    0.68067     1    0.35714    0.35714    1.00000     .
        3    0.68067     2    0.75571    0.75571    0.35714    1.00000
        4    0.68067     3    0.33271    0.33271    0.75571    0.35714
        5    0.68067     4    0.57739    0.57739    0.33271    0.75571
        6    0.68067     5    0.29729    0.29729    0.57739    0.33271
        7    0.68067     6    0.44545    0.44545    0.29729    0.57739
        8    0.68067     7    0.25860    0.25860    0.44545    0.29729
        9    0.68067     8    0.34658    0.34658    0.25860    0.44545
       10    0.68067     9    0.22085    0.22085    0.34658    0.25860
       11    0.68067    10    0.27162    0.27162    0.22085    0.34658