Rick is a good man．He makes birthday cakes in a shop．His cakes are great and have very good prices，so many people buy his cakes．He makes friends with lots of his customers(顾客)．They all like him very much．One evening．he wants to go home，but many of his old customers come in．Rick smiles(微笑)to them，“I am sorry．It is late today．If you need cakes，please come tomorrow．”One of them takes out a nice cake and says to him，“You make so many great cakes for us．This birthday cake is for you．Happy birthday, Rick．”

①ω=3；②ω≠6k，k∈N^*；③φ可能等于 $\frac{3}{4}\pi$ ；④符合条件的ω有无数个，且均为整数．

其中所有正确的结论序号是____．