If possible please tell me where your frind got question.

Net can give us a lot of knowledge and challenge.The students can give us more and more questions.


n=16k or n=16k+1 we have solution.
1,8,15,6,13,4,11,2,9,16,7,14,5,12,3,10.
17,................................,26.
33.................................,42.
49.................................,58.
65.................................,74.
81....................96...........,90,97.