已知等差数列{an}的前n项和Sn满足:Sn=n2+2n+a(n∈N*),则实数a=______.
已知等差数列{an}的前n项和Sn满足:Sn=n2+2n+a(n∈N*),则实数a=______.
设数列{an}前n项和为Sn,数列{Sn}的前n项和为Tn,满足Tn=2Sn-n2,n∈N*.
设等比数列{an}的前n项和Sn=2n+a,等差数列{bn}的前n项和Tn=n2-2n+b,则a+b=______.
已知数列{an}的前n项和为Sn,满足Sn=2an+n2-4n(n=1,2,3,…).
求证等差数列!已知数列an的各项均为正数,前n项和为Sn,且满足2Sn=a∧2n+n-4
已知数列{a(n)}Sn是其前n项的和,且满足3an=2Sn+n(n∈N※)
已知等差数列An 满足a1+a(2n-1)=2n,设Sn是1/An的前n项和.记f(n)=S(2n)-Sn
已知等差数列{an}的前n项和为Sn,且(2n-1)Sn+1 -(2n+1)Sn=4n²-1(n∈N*)
已知:数列{an}的前n项和Sn=n2+2n(n∈N*)
已知数列{an}的前n项和为Sn,且Sn=2n2+n,n∈N*,数列{bn}满足an=4log2bn+3,n∈N*.
已知数列{an}满足a1=0,an+1+Sn=n2+2n(n∈N*),其中Sn为{an}的前n项和,则此数列的通项公式为
已知数列{an}满足ak+a(n-k)=2,(k,n-k∈N*),则数列{an}的前n项和Sn=