2^(6n+1)除以9的余数是2
2^(6n+2)除以9的余数是4
2^(6n+3)除以9的余数是8
2^(6n+4)除以9的余数是7
2^(6n+5)除以9的余数是5
2^(6n+6)除以9的余数是1
因为2^33=2^(6*5+3)
所以2^33除以9的余数是8