172期：01,06,07,08,11,12,14,17,18,19,21,23,25,26,27,28,31,32,33,34,37,45,46,48··（共半数）开21准
173期：01,03,04,08,10,11,12,14,16,17,18,21,22,24,26,29,30,31,32,38,41,42,44,46··（共半数）开20错
174期：01,05,06,09,10,12,13,15,16,17,23,26,27,31,32,33,36,37,39,40,41,42,43,47··（共半数）开？？！