RosettaCodeData/Task/Hofstadter-Q-sequence/PL-I/hofstadter-q-sequence-2.pli

   declare tally fixed binary (31) initial (0);

   do i = 1 to n-1;
      if Q(i) > Q(i+1) then tally = tally + 1;
   end;
   put skip data (tally);