（2n-1）•an=（2n-1）*2^nTn=1*2^1+3*2^2+.(2n-1)*2^n2Tn=1*2^2+3*2^3+5*2^4+.+(2n-3)*2^n+(2n-1)*2^(n+1)Tn-2Tn=2^1+2*2^2+2*2^3+.+2*2^n-(2n-1)*2^(n+1)-Tn=2+2^3+2^4+.+2^(n+1)-(2n-1)*2^(n+1)-Tn=2+8*[1-2...,6,
