等差数列An 满足A2=3 ,Sn-Sn-3=51 求Sn=100 n= 详解

等差数列An 满足A2=3 ,Sn-Sn-3=51 求Sn=100 n= 详解 在等差数列an中,a1=1.Sn为前n项和,且满足S2n-2Sn=n^2.求a2及an通向公式 数列{an}满足a2=3a1,Sn是数列{an}的前n项和,且有Sn+1+Sn+Sn-1=3n^2+2(n>=2,n属于N+)(1)若数列{an}为等差数列,求通项an;(2)若任意n属于N+,an 已知等差数列an的前n项和为Sn,且满足a2+a4=14,S7=70 a1=1,a2=6,sn=3sn-1-2sn-2+2^n（n大于等于3）求证：an/2^n是等差数列 等差数列{an}满足3a8=5a13,且a1>0,sn是前n项和,求sn最大值 已知等差数列{an}中,a1=-60,an+1=an+3,求Sn=|a1|+|a2|+…+|an| 设数列An的前n项和为Sn,满足2Sn=An+1 -2^n+1+1,且A1.A2+5.A3成等差数列 求数列的设数列An的前n项和为Sn,满足2Sn=An+1 -2^n+1+1,且A1.A2+5.A3成等差数列 求数列的通项公式 已知数列{an}有a1=a,a2=p(常数p>0),对任意的正整数n,Sn=a1+a2+...+an,并有Sn满足Sn=n(an-a1)/2(1)求a的值(2)试确定数列{an}是否是等差数列,若是,求出其通项公式,若不是,说明理由(3)对于数列{bn},假如存在一 已知数列an首相a1=3,通项an和前n项和SN之间满足2an=Sn*Sn-1（n大于等于2）求证1/Sn为等差数列 an通项公式 设数列an的前n项和为Sn,满足2Sn=an－2∧n+1 +1 ,且a1,a2+5,a3成等差设数列an的前n项和为Sn,满足2Sn=an－2∧n+1 +1 ,且a1,a2+5,a3成等差数列.求a1,an的通项 若俩个等差数列{an}和{bn}的前n项和分别为Sn和Tn,且满足Sn/Tn=7n-3/n+1,则a2+a5+a17+a22/b8+b10+b12+b16= 数列an满足sn=3an-1/2 计算a1,a2,a3,a4 猜an通项 求an前n项和sn 在等差数列an中,Sn-a1=48,Sn-an=36,Sn-a1-a2-an-1-an=21,求这个数列 已知数列an中,a1=2,a2=3,其前n项和Sn满足Sn +1+Sn -1=2Sn +1,求an的通项公式.补充：n＞＝2,前面不太正确,是：其前项和Sn满足Sn+1 +Sn-1 =2Sn +1 数列an中,a1=1,当n大于=2时,sn满足sn方=an(sn-1) 证明1/sn是等差数列 已知数列{an}的前n项和为Sn,且满足an+2Sn*Sn-1=0,a1=1/2.求证：{1/Sn}是等差数列 已知等差数列{an}满足a2+a4=4,a3+a5=10,求{an}的通项公式及{an}的前n项和sn