数列{an}满足 11/9 a1 + (11/9)^2 a2 + ...+ (11/9)^n an = 1/2 (n^2+n) 当an取得最大值时,n等于?

数列an满足a1=2,an+1=4an+9,则an=? 已知数列{an}满足3an+1+an=4,a1=9,求通项公式. 数列{An}满足a1=1/2,a1+a2+..+an=n方an,求an 数列{an}满足 11/9 a1 + (11/9)^2 a2 + ...+ (11/9)^n an = 1/2 (n^2+n) 当an取得最大值时,n等于? 已知数列{an}满足a1=1 an+1=an/(3an+1) 则球an 数列 (10 18:35:56)设数列{an}满足a1=9,an+1=-1/2an+3,求an的通项公式（含过程） 已知数列{an}满足an+1=an+n,a1等于1,则an=? 数列{an}满足a1=1 an+1=2n+1an/an+2n 已知数列{an}满足an+1=2an+3.5^n,a1=6.求an 数列an满足a1=2,an+1=an²求an 数列an满足a1=2,an+1=an²求an 数列[An]满足An+1-An+3=0,且A1=-5.求An. 数列｛an｝满足a1=1,且an=an-1+3n-2,求an 已知数列{an}满足a1+a2+...+an=n²an求其通项an 已知数列{an}满足：a1=9, 3a（n+1 ）+an=4,求通项公式 递增数列{an}满足a1=6,an+an-1=9/an-an-1+8(n>=2)则a70= 已知数列{an}满足3an+1+an=4,a1=9,前n项和为sn,则满足不等式/sn-n-6/ 已知数列{an}满足3an+1+an=4,a1=9,前n项和为sn,则满足不等式/sn-n-6/