题目有错,应为1+1/3+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110+1/132+1/156+1/182+1/210=1+1/3+1/2-1/3+1/+-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10+1/10-1/11+1/11-1/12+1/12-1/13+1/13-1/14+1...