for i :=  2  to  999  do
                   case i of
                         2 .. 4 : if i mod  2  =  0  then
                                             a[i+ 1 ] := a[i] +  20 . 33 
                                             else
                                             a[i+ 1 ] := a[i] +  20 . 34 ;
                         5 .. 9 : a[i+ 1 ] := a[i] +  19 ;
                         10 .. 19 : a[i+ 1 ] := a[i] +  18 ;
                         20 .. 59 : if i mod  2  =  0  then
                                               a[i+ 1 ] := a[i] +  12 . 13 
                                               else
                                               a[i+ 1 ] := a[i] +  12 . 12 ;
                         60 .. 69 : a[i+ 1 ] := a[i] -  1 . 5 ;
                         70 .. 999 : a[i+ 1 ] := a[i] +  15 . 71 ;
                   end;
...