数列｛an｝满足a1=1,a2=2,an+2=[1+cos（nπ/2）]an+sin（nπ/2）,n=1,2,3… （1）求a3,a4,并求数列｛an｝的通项公式 （2）设bn=a2n-1/a2n,Sn=b1+b2+…+bn 证明：当n≥6时,丨Sn-2丨＜1/n

数列{An}满足a1=1/2,a1+a2+..+an=n方an,求an 已知数列an满足an=1+2+...+n,且1/a1+1/a2+...+1/an 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,a2=3,an+2=3an+1-2an求an 已知数列an'满足a1=1/2,a1+a2+a3+...+an=n^2an,求通项公式 设数列AN满足A1等于1,3(A1+a2+~+AN)=(n+2)an,求通向公式 已知数列an满足a1=0 a2=1 an=(An-1+An-2)/2 求liman 已知数列an满足a1=0 a2=1 an=(An-1+An-2)/2 求liman 数列An,满足An=An-1 + An-2,其中,A1=1,A2=1,求通项公式. 若数列{an}满足a1=1,a2=5且an+2=an+1-an,求a2000 数列{an}满足a1=3,a2=6,an+2=an+1-an,求a2013 数列{an}满足a1=3,a2=6,an+2=an+1-an,求a2008 几个数列问题.已知数列{an} a1=1,an+1=an/(1+n^2*an) 求an 已知数列{an} 满足a1=1 a1*a2*a3.*an=n^2 求an 数列an满足a1=1,a2=1/3,并且an(an-1+an+1)=2an+1an-1.则数列第2012项为? 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 设数列{an}满足lg(1+a1+a2+...+an)=n+1,求通项公式an 已知递增数列{an}满足a1=1,(2an+1)=an+(an+2),且a1,a2,a4成等比数列.求an 已知数列{an}满足：a1+a2+a3+.+an=n^2,求数列{an}的通项an.