求an

求an通项式 等比数列求an 数列an中,(n+1)an+1-nan方+an+1an=0,求an 已知等差数列{an}中,a1=2.an+1=an+3分之an 求an 已知a1=2,an不等于0,且an+1-an=2an+1an,求an an ocean away 求歌词 求an endless tale MP3 an unforgetable day 求作文 求An amazing thing 作文 an unforgettable day 求一篇! a1=1 an+1=an/2an+3,用两种方法求an 数列an,a1=4,an+1=5^n*an,求an