已知正向数列｛an｝满足a1=1/2,且an+1=an/1+an.1/an=n+1,求和3/a1+3^2/a2+3^3/

已知正向数列｛an｝满足a1=1/2,且an+1=an/1+an.1/an=n+1,求和3/a1+3^2/a2+3^3/ 数列｛an｝满足a1=1,且an=an-1+3n-2,求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=? 已知数列{an}满足a1=1,an=a1+1/2a2+1/3a3+...+1/n-1an-1(n>1)求数列{an}的通 已知数列｛An｝满足（n+1)an-nan+1=2,且a1=3.求an的通项公式,（2）,求和：（a1+a2)+(a2+ 已知数列{an}满足,a1=2,a(n+1)=3根号an,求通项an 已知数列{an}满足a1=1,an=a1+2a2+3a3.+(n-1)an-1 (n>=2),则{an}的通项是什么 已知数列an满足a1=1.a2=3,an+2=3an+1-2an 已知数列{an}满足a1=1;an=a1+2a2+3a3+...+(n-1)a(n-1); 数列{an}满足：1/a1+2/a2+3/a3+…+n/an=2n