可以：log2(log216)=log2(log2(2^4))=log2(4)=log2(2^2)=2
log2(log216)=log2(log2（2^4）)=log2(4)=2
就是用的这个公式log2(log2 16)=log2(log2 2^4)=log2 4=log2 2^2=2
