Locker Mania

There is a locker room in the club and they are numbered from 1 to 100. There are 100 members of the club who will enter the locker room in the following sequence. When the first member enters, he opens all the lockers. When the second member enters the locker room, he closes all even numbered lockers. When the next member enters the room, he toggles the state of every locker which is a multiple of 3.

 This process continues till all the 100 members have been through the locker room. At the end of this process, which are the lockers that are open?