设an=1+1/2+1/3+.+1/(3n-1)则a(n+1)-an=

设数列,a1=3,an+1=3an-2,求数列an是等比数列 a1=1,Sn+1=4an+2,设bn=an+1-2an,设Cn=an/3n-1,证明Cn为等比数列 设数列{an}中,a1=1且an+1=3an+4,求证{an+2}是等比数列求{an}的前n项和为Sn 数列AN满足A1=2,AN+1=AN^2+6AN+6,设CN=LOG5(AN+3),证｛CN}为等比 设an=(1/n+1)+(1/n+2)+(1/n+3)+...+1/2n,则an+1-an等于? 设数列{an},a1=3,a(n+1)=3an -2 (1)求证:数列{an-1}为等比数列 设数列{an}中,a1=2,an+1=an+n+1,则通项an=? 设数列an a1=3 3an+1-3an=2 则a100=rt. 设数列﹛an﹜中,a1+4,an=3a(n-1)+2n-1,求通项an 设a0为常数,且an=3n－1－2an－1（nN+）.求an 设数列an的前n项和为Sn,若Sn=1-2an/3,则an= 设数列AN满足A1等于1,3(A1+a2+~+AN)=(n+2)an,求通向公式 数列{an}满足a1=3/2,an+1=an2-an+1,求证：1/an=1/(an)-1 - 1/(an+1)-1数列{an}满足a1=3/2,an+1=an2-an+1,求证：1/an=1/(an)-1 - 1/(an+1)-1设Sn=1/a1+1/a2+...+1/an,n>2证明1 设｛an｝是一个等差数列,a1=19,a21=3,记An=an+an+1+...+an+6,则|An|的最小值为 设数列{an}满足a1=1a2=2an=1/3（an-1+2an-2）求an题目为设数列{an}满足a1=1，a2=2，an=1/3（an-1+2an-2）求an 数列{an}满足a1=3/2,an+1=an2-an+1,求证：1/an=1/(an)-1 - 1/(an+1)-1 设Sn=1/a1+1/a2+...+1/an,n>2数列{an}满足a1=3/2,an+1=an2-an+1,求证：1/an=1/(an)-1 - 1/(an+1)-1设Sn=1/a1+1/a2+...+1/an,n>2证明1 设数列an满足a1=2,a(n+1)=3an+2^(n-1),求an2,设数列an满足a1=2,a(n+1)=3an+2n,求an 数列{an}中,a1=1,Sn+1=4an+2设bn=an+1-2an,求证{bn}是等比数列,设cn=an/3n-1,求证cn是等比数列.