已知数列an满足a1+2a2+3a3+……+nan=n(n+1)(n+2),则它的前n项和Sn=?
已知数列an满足a1+2a2+3a3+……+nan=n(n+1)(n+2),则它的前n项和Sn=?
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=?
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}满足a1+2a2+3a3+…+nan=n(n+1)(n+2),则它的前n项和Sn=______.
设数列an的前n项和为Sn 已知a1+2a2+3a3+……+nan=(n-1)Sn+2n
已知数列{an}的前n项和为Sn,且a1+2a2+3a3+…+nan=(n-1)Sn+2n(n∈N*),求数列{an}通
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}的前n项和为Sn,且 a1+2a2+3a3+…+nan=(n-1)Sn+2n(n∈N*).
已知数列{an}满足a1+2a2+3a3+…+nan=n(n+1)(n+2),则a1+a2+a3+…+an=多少?
设数列{an}的前n项和为Sn,a1+2a2+3a3.+nan=(n-1)Sn+2n,
已知数列{an}满足a1+a2+a3+…+nan=n(n+1)(n+2),则{an}的通项公式为an=
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