已知数列{an},a1=1,前n项和为Sn,且点P(an,an+1)(n∈N*) 发布时间:2017-05-03 22:43 │ 来源:www.tikuol.com 题型:选择题 问题: 已知数列{an},a1=1,前n项和为Sn,且点P(an,an+1)(n∈N*)在直线x-y+1=0上,则1S1+1S2+1S3+…+1Sn=( )A.n(n+1)2B.2n(n+1)C.2nn+1D.n2(n+1)