设{an}的前n项和为S,已知a1=1,a2=6,a3=11,(5n-8)Sn+1-(5n+2)Sn=a*n+b,n=1
设{an}的前n项和为S,已知a1=1,a2=6,a3=11,(5n-8)Sn+1-(5n+2)Sn=a*n+b,n=1
设数列{an}的前n项和为Sn,已知a1=1,a2=6,a3=11,且(5n-8)S(n+1)-(5n+2)Sn=A*n
设数列an的前n项和为Sn,a1=1,a2=6,a3=11,且(5n-8)S(n+1)-(5n+2)Sn=An+B,n=
设{an}的前n项和为S,已知a1=1,a2=6,a3=11,(5n-8)Sn+1-(5n+2)Sn= -20n-8.n
设数列An的前n项和为Sn,已知A1=1.A2=6,A3=11,且(5n-8)S(n+1)-(5n+2)Sn=-20n-
设数列{an}的前n项和为Sn,已知a1=1 a2=6 a3=11 且(5n-8)Sn+1-(5n+2)Sn =A*n+
设数列{An}的前n项和为Sn,已知A1=1,A2=6,A3=11,且(5n-8)S(n+1)—(5n+2)Sn=Pn+
数列{an}的前n项和为Sn,已知a1=1,a2=6,a3=11,且(5n-8)S(n+1)-(5n+2)Sn=An+b
设数列{an}的前n项和为sn,已知a1+2a2+3a3+…+nan=(n-1)Sn+2n(n∈N*)
设数列an的前n项和为Sn,已知S1=1,Sn+1/Sn=n+c/n,且a1,a2,a3成等差数列
已知数列an的前n项和为sn,且sn+an=1/2(n2+5n+2)(2属于n*) 计算a1 a2 a3 a4
已知数列an的前n项和为Sn=n^2+2n,求和:1/(a1*a2)+1/(a2*a3)+...+1/(an*a(n+1