数列an满足a1=1/2,nan+1(下标)-(n+1)an=n^2+n,求数列an/n的前n项和
数列an的前n项和Sn,a1=1,a(n+1)(下标)=2Sn.求通项an 求nan的前n项和Tn
已知数列an满足a1+2a2+3a3+...+nan=n(n+1)*(n+2),则数列an的前n项和Sn=?
已知数列{an}的前n项和为Sn,又a1=2,nAn+1=sn+n(n+1),求数列{an}的通项公式
数列{an}的前n项和为Sn,a1=1,an+1(n+1是下标)=2Sn+1,求数列{nan}的前n项和为Tn
数列an的前n项和为sn,且a1=2,nan+1=sn+n*(n+1),求数列an通项公式
已知数列an满足a1+2a2+3a3+……+nan=n(n+1)(n+2),则它的前n项和Sn=?
数列 an的前n项和为Sn,a1=1,an+1=2Sn 求数列{nan}的前n项和Tn
设数列an满足a1+2a2+3a3+.+nan=2^n 1求数列a的通项 2设bn=n^2an 求数列的前n项和Sn求大
数列an满足a1+2a2+3a3+...+nan=(n+1)(n+2) 求通项an
已知数列(an)满足a1+2a2+3a3+...+nan=n(n+1)(n+2)求an
设数列{an}满足a1+2a2+3a3+.+nan=n(n+1)(n+2)
已知数列{An}满足:A1=1,An=nAn-1+(n-1)!(n>=2),求数列{An}的通项公式.