一道数列题：若a1=1,a2=1,an=a(n-1)+2a(n-2),n>=3

一道数列题：若a1=1,a2=1,an=a(n-1)+2a(n-2),n>=3 整数数列{An}满足 A1*A2+A2*A3+…+A(n-1)*An=(n-1)*n*(n+1)/3 ,(n=2,3,… 已知数列{an}满足a1=1,an=a1 +1/2a2 +1/3a3 … +1/(n-1)a(n-1),(n>1,n∈N 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 设数列{an}满足a1+3a2+3^2a3+.3^n-1×an=n/3,a∈N+. 求解一道数列证明题已知a(n)=2∧n-3∧n 求证1/a1 +1/a2 +……+1/an ＜3/2 已知数列{an}满足a1=1;an=a1+2a2+3a3+...+(n-1)a(n-1); 能再问您一道吗?在数列an中,a1=3,a2=6,a(n+2)=a(n+1)-an,则数列第五项 数列an中,a1=1/4 ,当n>=2时,有(3n^2-2n-1)an=a1+a2+a3+.+a(n-1) 已知数列{an}满足a1=1,a2=3,a(n+2)=3a(n+1)-2an 数列an满足a1=2,a2=5,a(n+2)=3a(n+1)-2an 已知数列An满足A1=1,An=3^(n-1)+A(n-1)(n=>2).(1)求A2,A3;(2)证明An（3^n-1