证明连续四个奇数减一能被八整除

题目有误吧：证明连续四个奇数的乘积减一能被八整除
设四个连续奇数为2n-3,2n-1,2n+1,2n+3,n是整数
(2n-3)(2n-1)(2n+1)(2n+3)-1
=[(2n-3)(2n+3)]*[(2n-1)(2n+1)]-1
=(4n²-9)(4n²-1)-1
=16n^4 -10*4n²+9-1
=16n^4 -5*8n²+8
每项都含有因数8
所以 ,这个数能被8整除