设数列(an)对一切正整数n均有an=2*[a(n+1)]^2-1 且an>0,如果a1=cos2A,

设数列an满足a1=a2=1,a3=2,且对正整数n都有an·an+1·an+2·an+3=an+an+1+an+2+a 数列an=3^n - 2^n 证明:对一切正整数n 有1/a1 + 1/a2 +…+ 1/an 已知数列｛an｝满足an>0且对一切n属于正整数,都有a1^3+a2^3+...+an^3=sn^2,sn是｛an｝的前 已知等差数列an的首项a1为a,设数列的前n项和为Sn,且对任意正整数n都有a2n/an=4n-1/2n-1,求数列的通 设数列｛an｝满足an+1/an=n+2/n+1,且a1＝2 在数列{an}中,a1=2010,且对任意正整数,都有a(n+2)=a(n+1)-an,则a2+a3+a4+……+a20 设数列{An}满足An+1=An^2-nAn+1,n为正整数,当A1>=3时,证明对所有的n>=1,有 设数列｛an｝的各项都是正数,且对任意n属于N+,都有an(an+1)=2(a1+a3+.+an). 设数列{an}中,a1=2,a(n+1)=an+n+1,求an 设数列{An}满足A1+3A2+3^2*A3+...+3^(n-1)*An=n/3,a属于正整数. 设函数f(x)=1/x,数列an满足：a1=a不等于0,且对于任意的正整数n都有an+1=f(an^2),则a1*a2… 设各项均为正数的数列{an}的前n项和为sn已知a1=1且(Sn+1+λ)an=(Sn+1)an+1对一切n∈正整数成立