已知数列{an}满足a1+2a2+3a3+...+nan=n(n+1)(2n+1),则该数列an=?
已知数列{an}满足a1+2a2+3a3+...+nan=n(n+1)(2n+1),则该数列an=?
数列an满足a1+2a2+3a3+...+nan=(n+1)(n+2) 求通项an
设数列{an}满足a1+2a2+3a3+.+nan=n(n+1)(n+2)
已知数列(an)满足a1+2a2+3a3+...+nan=n(n+1)(n+2)求an
已知数列{an}满足a1+2a2+3a3+…+nan=n(n+1)(n+2),则a1+a2+a3+…+an=多少?
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=?
若数列{an}满足a1+2a2+3a3+~~+nan=n(n+1)(2n+1),则an=
已知数列{an}满足:a1+2a2+3a3+...+nan=(2n-1)*3^n(n属于正整数)求数列{an}得通项公式
已知数列an满足a1+2a2+3a3+……+nan=n(n+1)(n+2),则它的前n项和Sn=?
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=
已知数列an满足a1+2a2+3a3+……+nan=2^n,求an
在数列{an}中,a1+2a2+3a3+.+nan=n(2n+1)(n属于N)