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
等差数列{an}满足a1=1,且a1、a2、a4成等比数列,求an
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
已知数列{an}满足a1+a2+a3+...+an=n^2+2n.(1)求a1,a2,a3,a4
已知递增等差数列{an}满足:a1=1,且a1,a2.a4成等比.(
已知数列(an)满足a1=1,an+1=2an/an+2(n∈N*) 求a2,a3,a4,a5 猜想数列(an)的通项公
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=1,a2=3,an+2=3an+1-2an求an
已知{an}满足a1=1,an+1=an/an+2(n属於N*) (1)求a2 a3 a4 (2)猜想数列{an}的通项
已知数列{an}满足:a1+a2+a3+…+an=n-an 求证{an-1}为等比数列 令bn=(2-n)(an-1)求
已知数列{an}中,a1=-1,a2=4,an+2+2an=3an+1 求证:数列{an+1-an}是等比数列,并求{a
已知数列{an}满足a1=2且anan+1-2an=0球a2,a3,a4的值