数列{an}是以a1=4为首项的等比数列，且S3,S2,S4成等差数列

1.
2S2=S3+S4
2S2=S2+A3+S2+A3+A4
2A3+A4=0
A4/A3=-2
An=A1×q^n=4×(-2)^(n-1)=(-2)^(n+1)

2.
|An|=|(-2)^(n+1)|=2^(n+1)
Bn=log2|An|=log2(2^(n+1)=n+1
1/(Bn×B(n+1)=1/((n+1)×(n+1+1))=((n+2)-(n+1))/((n+1)(n+2))=1/(n+1)-1/(n+2)
Tn=(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+……+(1/(n+1)-1/(n+2))
=1/2-1/(n+2)
=n/(2(n+2))

q=0(舍)或q=-2

an=4*(-2)的n-1次方