数列{an满足a1=1,a2=2/3,且1/(an-1)+1/(an+1)=2/an,n≥2,n∈正整数,则an=( )

已知数列an满足an=1+2+...+n,且1/a1+1/a2+...+1/an 【高中数学数列】已知数列an满足a1=1,a2=2,且an=an-1/an-2 (n大于等于3)则a2012=? 数列{An}满足a1=1/2,a1+a2+..+an=n方an,求an 若数列{an}满足a1=1,a2=5且an+2=an+1-an,求a2000 已知数列an满足an=1+2+...n,且（1/a1）+(1/a2）+...(1/an) 求数列数列{an}满足a1=1,且n≥2时,an=a1+2a2+3a3+•••+(n-1)an-1的通项公式求数列{an}满足a1=1,且n≥2时,an=a1+2a2+3a3+•••+(n-1)an-1的通项公式 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=1,a2=2,且 an+2=(2+cosnπ)(an-1)+3,n∈N+（1）求an 已知数列{an}满足:a1=1,a2=2,且 an+2=(2+cosnπ)(an-1)+3,n∈N+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=1,且an-an-1=2n,求(1)a2,a3,a4.(2)求数列{an}的通项an 已知数列{an}满足a1=1,a2=3,an+2=3an+1-2an求an 数列｛an｝满足a1=1,且an=an-1+3n-2,求an 已知数列{an}满足a1=2且anan+1-2an=0球a2,a3,a4的值 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 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 a1+a2+...+ak=a1×a2×...×ak,an+k=k+an(N属于正整数已知各项均为正整数的数列an满足an≤an+1,且存在正整数k,使得a1+a2+...+ak=a1×a2×...×ak,an+k=k+an（N属于正整数）（1）求数列{an}的通项公式；（2）若数列b