数列求教.判断Sn有无极限.有就求出，无就证明.

(8k-8+m)=a(9k-9+m)=9k-9+m,m=1,2,...,8.k=1,2,...
c(n)=1/a(n)=1/n,
t(n) = c(1)+c(2)+...+c(n) = ln(n) + C ,其中,C为欧拉常数.t(n)与ln(n)为同阶无穷大.
s(8n) = t(9n) - t(n)/9 = ln(9n)+ C - [ln(n) + C]/9 =(8/9)ln(n) + ln(9) - 8C/9,s(8n)与ln(n)为同阶无穷大.
s(8n-1)=s(8n)-1/(8n) = s(8n),
s(8n-2)=s(8n-1)-1/(8n-1) = s(8n-1) = s(8n),
s(8n-3)=s(8n-2)-1/(8n-2) = s(8n-2) = s(8n).
...
s(8n)-7 = s(8n).
s(8n-7),s(8n-6),...,s(8n-1),s(8n)都是ln(n)的同阶无穷大.
s(n)无极限.s(n)->无穷大.

问题呢，翻上来吧