an/a(n-1)=1×2^(n-1)=2^(n-1)a(n-1)/a(n-2)=2^(n-2)…………a2/a1=2连乘an/a1=2×2²×...×2^(n-1)=2^[1+2+...+(n-1)]=2^[n(n-1)/2]an=a1×2^[n(n-1)/2]=1×2^[n(n-1)/2]=2^[n(n-1)/2]a6=2^(6×5/2)=2^15=3276...