设数列{an}的前n项和为Sn,已知1/S+1/S2+…1/Sn=n/n+1

设数列{an}的前n项和为Sn,已知1/S+1/S2+…1/Sn=n/n+1 设数列｛an｝的前N项和为Sn,已知1/Sn+1/S2+1/S3+.+1/Sn=n/(n+1),求Sn 设数列{an}的前n项和为Sn,已知1/S+1/S2+…1/Sn=n/n+1,设bn=(1/2)^an,数列{bn}的前 设数列{an}前n项和为Sn,已知(1/S1)+(1/S2)+.+(1/Sn)=n/(n+1),求S1,S2及Sn 设数列｛an｝的前n项和为Sn 已知1/S1+1/S2+ 已知数列an的首项a1=5,前n项和为Sn,且S(n+1)=2Sn+n+5（n∈N*）,求数列｛an｝的前n项和Sn,设 设 数列｛an｝的前n项和为Sn,已知b*an - 2^n=(b-1)Sn 设数列{an}的前n项和为sn,已知a1+2a2+3a3+…+nan=(n-1)Sn+2n(n∈N*) 已知数列{an}的通项公式an=log2[(n+1)/(n+2)](n∈N),设其前n项的和为Sn,则使Sn 设数列an的前n项和为Sn,a1=1,an=(Sn/n)+2(n-1)(n∈N*) 求证:数列an为等差数列, 设数列{an}的前n项和为Sn,已知Sn=2an-2n+1,（n为下标,n+1为上标）,求通项公式? 设数列an的前n项和为Sn,已知a1=1,(2Sn)/n=a(n+1)-1/3n^2-n-2/3