I added the seeds to “/help seeds” a few days ago, but for redundancy, here they are:

Alpha: -621778714517541268
Delta: -8443156782283251243
Gamma: -754633420005903009

Seeds were removed from the debug screen because many servers — for survival purposes — didn’t want people generating the same world and flying around to find stuff. It probably should be optional, but it’s not a big deal.