设数列{an}的前n项和为sn,sn=a1(3^n-2)/2(n≥1),a4=54,则a1=

设数列{an}的前n项和为sn,sn=a1(3^n-2)/2(n≥1),a4=54,则a1= 设数列an的前n项和为Sn,a1=1,an=(Sn/n)+2(n-1)(n∈N*) 求证:数列an为等差数列, 设数列{an}的前n项和为Sn,若a1=1,Sn=2an+Sn+(n∈N+),则a6= 设数列an的前n项和为Sn,已知a1=1,(2Sn)/n=a(n+1)-1/3n^2-n-2/3 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的首项a1等于1,前n项和为sn,sn+1=2n 设数列an的前n项和为Sn,a1=1 ,an = 2Sn²/2Sn-1 （n≥2） 设数列An的前n项和Sn=2An-2n的次方,求A1,A4 设数列an的前n项和为Sn,已知a1=1,Sn+1=4an+2 设Sn是数列an的前n项和,已知a1=1,an=-Sn*Sn-1,（n大于等于2）,则Sn= 数列{an}的前n项和为sn=n2+3n+1,则a1+a2+a3+a4+a5 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