有一列数a1,a2,a3.......an,从第二个数开始,每一个数都等于1与它前面那个数的倒数的差,若a1=2,则a2011为()
Li Ping is a Grade Eight student in Nanjing Sunshine Secondary School. The table below is his mid-term self-assessment(自我评价).He draws faces to show his progress: