The pattern is: subtract 16, then 8, then 4, then 2, then 0.5. Checking: 36-16=20, 20-8=12, 12-4=8, 8-2=6, 6-0.5=5.5, 5.5-0.5=5. So the term should be 5, not 5.5. The difference being subtracted is being halved each time (16, 8, 4, 2, 1, 0.5...). But we have 0.5 twice instead of 1 then 0.5. So 5.5 is the wrong term.