记数列{an}的前n项和为Sn,且Sn=2(an-1),则a2=______.
记数列{an}的前n项和为Sn,且Sn=2(an-1),则a2=______.
记数列(an)的前n项和为Sn已知a1=1,对任意n∈N*,均满足an+1=(n+2)/n)Sn
等差数列an中,公差d>0,且a5+a10=0,记数列-2/an的前n项和为Sn,则使Sn
已知an=2^n-1/2^n,记数列{1/an}的前n项和为Sn,求证Sn<4/3.
记数列{an}的前n项和为Sn,若{Sn/an}是公差为d的等差数列,则{an}为等差数列的充要条件是d=?
记数列An前n项积为Tn=1-An,记Cn=1/Tn.数列bn的前n项和为Sn且Sn=1-bn.(1)证明Cn是等差数列
已知{an}的前n项和为Sn,且满足log2(Sn+1)=n+1,则an=______.
已知等比数列{an}中,a4-a2=a2+a3=24,记数列{an}的前n项和为Sn,
已知正数列{an}的前n项和为Sn,有a1^3+a2^3+a3^3+.+an^3=Sn^2.(1)求an
记数列{an}的前n项和为Sn,若3a(n+1)=3an+2 n属于N+,a1+a3+a5+...+a99=90
数列{an}的前n项和为Sn,且Sn=2an-1,则{an}的通项公式为an= ___ .
Sn=n^2,设bn=an/3/,记数列{bn}的前n项和为Tn