Logic or macro series created by entering single value in cell

hii need solution for excel

i have series which is to be called / created by entering single value in cell

for e.g i hv to call series for 55 it consist of series starts from 33 to 54 by increment of 3 and 0.5 from 54 to 55 ( 33 36 39 42 45 48 51 54 54.5 55)
similarly for 100 (33 36 39 42 ..........99 99.5 100)
similarly for 90 ( 33 36 39 42 45 ...........89 89.5 90)

if i will enter 95 in A2 cell then A3 would be 33 A4-36 ,A5-39,A6-42...as on A24-94,A25-94.5,A26-95

plz help