等差数列{an}的前n项和为Sn,公差为d,已知(a8+1)^3+2013(a8+1)=1,（a2006+1）^3+2013（a2006+1）=-1则求d与0大小关系,S2013=?

等差数列{an}的前n项和为Sn,公差d 记数列{an}的前n项和为Sn,若{Sn/an}是公差为d的等差数列,则{an}为等差数列的充要条件是d=? 已知{an}是首项为19,公差为-2的等差数列,Sn为｛an｝的前n项和, 已知公差不为0的等差数列{An}的首项A1=1,前n项和为Sn,若数列{Sn/An}是等差数列,求An? 已知等差数列{an}的首项为4,公差为4,其前n项和为Sn,则数列{1/Sn}的前n项和为 已知等差数列an的公差为d,前n项和Sn＝－n^2,则通项公式为 设等差数列{an}公差d是2,前n项和为Sn,则lim(an^2-n^2)/Sn 设等差数列{an}公差d是2,前n项和为Sn,则lim(an^2-n^2)/Sn 数列前n项和为sn,a1=1,an+sn是公差为2的等差数列,求an-2是等比数列,并求sn 设公差为d的等差数列{an}的前n项和为Sn,若a1=1,-2/17 等差数列An的首项为a1等于3公差等于2前n项和为Sn求数列.1/Sn的前n项和Tn 设Sn为等差数列{An}的前n项和,若S5=20 S10=-35则公差为 设等差数列an的前n项和为sn,若s4/12-s3/9=1,则公差为? 设数列{an}的前n项和为Sn,若{an}和{根号sn+n}都是公差为d的等差数列,则a1= 已知{an}是首项为19,公差为-2的等差数列,Sn为{An}的前n项和,求通项a、b及前n项和S 等差数列｛an｝前n项和为Sn,且Sn=3n^2+n 求公差d 设Sn为等差数列an的前n项和.求证Sn/n为等差数列 极限的简单运算2设等差数列an的公差为2,前n项和为Sn,则lim ((an^2-n^2)/Sn)=?