已知数列{an}满足.an=1/n+1+1/n+2+.+1/2n.证明：an≥1/2对一切正增数恒成立

已知数列{an}满足an+1=an+n,a1等于1,则an=? 已知数列{an}满足an+1=2an+3.5^n,a1=6.求an 已知数列{an}满足a(n+1)=an+n,a1=1,则an= 已知数列{An}满足A1=1,An+1=2An+2^n.求证数列An/2是等差数列 已知数列an满足an=1+2+...+n,且1/a1+1/a2+...+1/an 已知数列{an}满足a1=1,an+1·an=2^n 则s2012 已知数列{an}满足a(n+1)=an+lg2,a1=1,求an 已知数列{an},满足a1=1/2,Sn=n²×an,求an 已知数列{an}满足a1=1/2,sn=n^2an,求通项an 已知数列an满足a1=1/2 sn=n平方×an 求an 已知数列An满足 A1=1/2 Sn=N²An 求An 已知数列{an}满足：an+1=an+n,且a61=2002,则a1等于 已知数列an满足a1=1 Sn=2an+n 求an 周期性数列问题i已知数列｛an}满足a(n+1)=2an (0 已知数列an满足a1=4,an=n+1/n-1乘以an-1则an= 已知数列{an}满足a1=1/2,an+1=an+1/n的平方+n求an 已知数列an满足a1=1/2,an+1=an+1/n²+n,求an 已知数列an满足an+1/an=n+2/n且a1=1,则an=