设{an}是斐波那契数列,则a1=a2=1,an=a(n-1)+a(n-2)(n≥3),试画出求斐波那契数列前20项的程
设{an}是斐波那契数列,则a1=a2=1,an=a(n-1)+a(n-2)(n≥3),试画出求斐波那契数列前20项的程
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
数列问题, 设数列{an}的前n项和为Sn,a1=1,a2=2,a(n+2)=an+3,(n属于正整数),则S100等于
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
设数列{an}的前n项和为Sn,并且满足2Sn=an²+n,an>0.(1)求a1,a2,a3.(2)猜想{a
设数列an满足a1+3a2+3^2a3+……+3^(n-1)an=n/3,a是正整数,设bn=n/an,求数列bn的前n
设数列{an}满足a1+3a2+3^2a3+.3^n-1×an=n/3,a∈N+.
已知数列an的前n项和为Sn=n^2+2n,求和:1/(a1*a2)+1/(a2*a3)+...+1/(an*a(n+1
在数列an中a1=2,a(n+1)下标=4an-3n+1 1设bn=an-n求证bn是等比数列 2求数列an的前n项和s
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}的前n项和为Sn,a1=a ,a2=p(p>0),Sn=n(an-a1)/2