a3=a1+2d=2,a6=a1+5d=8,a1=-2,d=2 (1)an=2n-4
bn=2^(n-2)
Cn=(2n-4)*2^(n-2)=(n-2)*2^(n-1)
数列{anbn}前n项和Tn
Tn=(n-1)*2^n-1