已知数列﹛an﹜,满足a1=4,a2=2,a3=1,数列﹛an+1-an﹜为等差数列,则an的通项公式为?an+1,指的是角标n+1

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+a2+a3+.+an=n^2,求数列{an}的通项an. 已知数列﹛an﹜,满足a1=4,a2=2,a3=1,数列﹛an+1-an﹜为等差数列,则an的通项公式为?an+1,指的是角标n+1 已知数列an'满足a1=1/2,a1+a2+a3+...+an=n^2an,求通项公式 已知数列{an}满足a1=1,a2=3,an+2=3an+1-2an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=1/2,a1+a2+..+an=n方an,求an 已知数列{an}满足a1+a2+...+an=n²an求其通项an 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 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 已知数列{an}满足a1=4/3,2-a(n+1)=12/an+6则1/a1+2/a2+.1/an=? 已知数列an满足a1=1,an=a1+2a2+3a3+4a4+.(n-1)a(n-1),求通项an 已知数列{An}满足a1=1,a2=5,an+1=5an-4an-1,（n≥2）,求an 已知数列an满足an=1+2+...n,且（1/a1）+(1/a2）+...(1/an) 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) 已知数列{an}满足a1=½,a1+a2+.+an=n²an,求其通项an 已知数列{an}满足a1=½,a1+a2+.+an=n²an,求其通项an