通项问题如何解决？

sdcar2010

The reason is that let m = 2*p - 1 and m = 2*p, wherein p is a positive integer, then m is a positive ineger as well.

Therefore, N = 3m + 1 has two series: 1) N = 6*p -2; and 2) N = 6*p +1.  This is contrary to the claim that N = 6n + 3.