已知数列an的前n项和为Sn,a1=1,Sn=2an+1,则Sn=?

已知数列{an}a1=2前n项和为Sn 且满足Sn Sn-1=3an 求数列{an}的通项公式an 已知数列{an}的前n项和为Sn,且满足Sn=Sn-1/2Sn-1 +1,a1=2,求证{1/Sn}是等差数列 已知数列{an}的前n项和为Sn,且满足an+2Sn*Sn-1=0,a1=1/2.求证：{1/Sn}是等差数列 数列｛an}的前n项和为Sn,已知a1+2,Sn+1=Sn-2nSn+1Sn,求an 数列An的前n项和为Sn,已知A1=1,An+1=Sn*(n+2)/n,证明数列Sn/n是等比数列 设Sn是数列an的前n项和,已知a1=1,an=-Sn*Sn-1,（n大于等于2）,则Sn= 已知数列 an前n项和为Sn,a1=1,Sn=2a(n+1),求Sn 已知数列an的前n项和为sn,且a1=1,an+1=1/2sn 已知数列{an}的前n项和为Sn,且a1=1,an+1=1/2Sn. 设数列an的前n项和为Sn,已知a1=1,Sn+1=4an+2 已知数列an的前n项和为Sn,a1=1,Sn=2an+1,则Sn=? 已知数列An中,其前n项和为Sn,A1=1,且An+1=2Sn,求An的通项公式和Sn