设an=1+1/2+1/3+...1/(3n-1),（n∈N+）则a（n+1）-an等于

设数列,a1=3,an+1=3an-2,求数列an是等比数列 设数列{an}中,a1=2,an+1=an+n+1,则通项an=? 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}满足an=2an-1+n 若{an}是等差数列,求{an}通项公式 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 设数列{an}中,若an+1 =an+ an+2 (n∈N*),则称数列{an}为“凸数列” .设数列{an}为“凸数列”求第二问证明设数列{an}中,若an+1 =an+ an+2 (n∈N*),则称数列{an}为“凸数列” .设数列{an}为“凸数列”,若a1 =1, 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+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 a1=3 3an+1-3an=2 则a100=rt. 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a0=1,an+1= an+1/an,求证,lim(an/√(2n))=1谢了 设数列{an}满足a1=1, an=(4an-1 +2)/(2an-1 +7) ,则通项xn=? 设数列{an}中,a ₁= 2,an+₁=an+n+1,则通项an=