已知数列｛an｝满足an+an+1=2n+1（n∈N*）,求证：数列｛an｝为等差数列的充要条件是a1=1.

已知数列{an}满足an+1=2an+3.5^n,a1=6.求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a1=1/2,sn=n^2an,求通项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a1=1 Sn=2an+n 求an 已知数列an满足1/a-an=2根号n,且an>0.求an的通项公式是数列{an}满足1/an-an=2根号n，且an>0，求an的通项公式。 已知数列an满足an+1/an=n+2/n且a1=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a1=33,an+1-an=2n 则求an/n的最小值 已知数列{an}满足a1=33,an+1-an=2n 则求an/n? 已知数列an满足a1=33 an+1 -an=2n 则an/n的最小值是? 已知数列{an}满足a1=33,an+1-an=2n,则an/n的最小值为 已知数列{An}满足A1=33.,An+1-An=2n,则An/n的最小值是