数列an满足a1=2 ,a2=1,且( an-1 -an )/anan-1 =(an -an+1 )/anan+1 (n大于等于2),求a100 =

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+..+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) 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=2且anan+1-2an=0球a2,a3,a4的值 【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=? 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 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 数列an满足a1=2 ,a2=1,且( an-1 -an )/anan-1 =(an -an+1 )/anan+1 (n大于等于2),求a100 = 已知正项数列｛a｝满足a1=1/2,且a(n+1)=an/(1+an) 1,求正项数列｛a｝的通项公式 2,求和:a1/1+a2/2+.2,求和:a1/1 + a2/2 +......+an/n 数列an满足a1=1/2,a1+a2+a3……an=n^2an,则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 已知数列{an}满足:a1=1,a2=2,且 an+2=(2+cosnπ)(an-1)+3,n∈N+（1）求an 若数列{An}中满足a1=1,a2=2,且an=an-1/an-2,则a2013= 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 若数列an满足 a1=2011,a2=2012,且An+2=(An+1 +1)/An ,求a2012=?