设数列an=(2n+1)/(3n+1),(n=1,2,3,...)
设数列{an},a1=3,an+1=3an-2(n∈N*)
设数列{an}满足a1+2a2+3a3+.+nan=n(n+1)(n+2)
设数列an满足a1+3a2+3^2a3+.+3^n-1an=n/3,n∈N*,求数列an的通项公式
设数列{an}满足a1+3a2+3^2a3+.3^n-1×an=n/3,a∈N+.
an=3*2^(n-1),设bn=n/an求数列bn的前n项和Tn
3 数列{an}的通项公式an=(-1)^(n-1)*2n(n属于N*)设其前n项和为Sn,则S100=
数列Sn=(3n+1)/2-(n/2)an
设数列{an}中,a1=1且(2n+1)an=(2n-3)a(n-1),(n大于等于2),求{an},sn
设数列{an}满足a1+3 a2+3^2 a3+……+3^n-1 an=n/3,a属于N* 求数列{an}的通项
已知an=5n(n+1)(n+2)(n+3),求数列{an}的前n项和Sn
设数列{an}的前n项和Sn=-3n^2+6n+1,求通项公式
设数列an满足a1=2 an+1-an=3-2^2n-1