Can a stolen Android be tracked if it was factory reset?

Short answer, your phone can not be tracked in any any useful way.  If your phone has been missing for more than a couple of days it is never coming back.

Can the phone be tracked?  Yes.  If the IMEI of the phone is transmitted to a cell phone network, the location of the phone can be triangulated.  Is anyone going to do this for you?  No.  Certainly not for a $40 phone.  Note that a thief can circumvent triangulation by turning off the phone or switching it to airplane mode.

Alternatively, an app could programmatically read the IMEI, send it to a server and use the IP address to get a rough idea of where the phone is located.  Technically speaking, this is tracking the phone.  Will this help you?  No.  You will not have access to that information.  This unlikely non-solution requires having a shady app installed after a factory reset.

Chances are, the thief wiped your phone and you will never see it again.  You can report the phone as stolen and your carrier will blacklist it.  The will prevent future owners from using the phone on the same network.  If the phone is unlocked, it can generally still be used on another network- potentially in another country.  Worst case scenario, a blacklisted phone can be used as a wifi only device.

Do make sure your phone has not been misplaced.  Try calling your phone just in case.  Smartwatches may have a "find my phone" app or feature.