数列An 满足 a1+2a2+3a3+.+nan=n(n+1)(n+2) 求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
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a1+a2+a3+…+an=多少?
已知数列an满足a1+2a2+3a3+……+nan=2^n,求an
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}满足a1+2a2+3a3+...+nan=n(n+1)(2n+1),则该数列an=?
在数列{an}中,a1+2a2+3a3+.+nan=n(2n+1)(n属于N)
已知数列{an}满足a1+a2+a3+...+an=n^2+2n.(1)求a1,a2,a3,a4
在数列{an}中,对任意的正整数n,a1+2a2+3a3+...+nan=n(n+1)(n+2)成立,求an.