1+1/3+1+1/15+1+1/35+1+1/63+1+1/99+1+1/143+1+1/195+1+1/255
=8+(1/2)(1-1/3+1/3-1/5+...+1/15-1/17)
=8+(1/2)(1-1/17)
=8又8/17