数列{an}满足a1=2,a2=5,a（n+2）-3a(n+1)+2an=0.(1)bn=a（n+1）-2an,判断{bn}是什么数列.(2)求数列{an}的通项公式.（3）求数列{an}的前n项和Sn.

已知数列{an}满足条件:a1=5,an=a1+a2+...a(n-1) n大于等于2,求数列{an}的通项公式 数列{An}满足a1=1/2,a1+a2+..+an=n方an,求an 已知数列满足a1=1/2,an+1=2an/(an+1),求a1,a2已知数列满足a1=1/2,a(n+1)=2an/(an+1),求a1,a2;证明0 数列an满足a1=2,a2=5,a(n+2)=3a(n+1)-2an,求数列{an}的通项公式 已知数列{an}中满足a1=1,a(n+1)=2an+1 (n∈N*),证明a1/a2+a2/a3+…+an/a(n+1) 若数列{an}满足a1=1,a2=5且an+2=an+1-an,求a2000 (1)数列{an}中,a1=1,a2=-3,a(n+1)=an+a(n+2),则a2005=____(2)已知数列｛an｝满足a1=1,a1×a2×a3…an=n^2,求an. 已知数列{an}满足a1=a,a2=b,a(n+1)=a(n+2)+an,求a2012 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a(n+2)=a(n+1)-an,a1=1,a2=2,求a2005 已知数列{an}满足,a1=1,a2=2,a(n+1)=a(n+2)+an,求a2011? 已知数列{an}满足a1=1,a2=3,a(n+2)=a(n+1)-an,求S2012 数列{an}满足 a1=2,a2=5,an+2=3an+1-2an.(1)求证:数列{an+1-an}是等比数列; (2)数列{an}满足 a1=2,a2=5,a（n+2）=3a（n+1）-2an.(1)求证:数列{a（n+1）-an}是等比数列;(2)求数列{an}通式（3）求数列{an}前n项和SnPS：求 数列an满足a1=2,a2=5,a(n+2)=3a(n+1)-2an(1)求证：数列{a(n+1)-an}是等比数列（2）求数列{an}的通向公式 数列an满足a1=1/2,a1+a2+a3……an=n^2an,则an 已知数列｛an｝满足：a1=1,且an-a（n-1）=2n.求a2,a3,a4.求数列｛an｝通项an 设数列{an}满足：a1+a2/2+a3/3+a4/4……+an/n=An+B,其中A、B为常数.数列{an}是否为等差数列? 已知数列{an}满足：a1+a2+a3+.+an=n^2,求数列{an}的通项an.