Factorial Town - Digimon World 1
Factorial Town is one of the last areas of the game and can only be accessed if you have recruited Whamon. Speaking with him in File City will allow you to sail out to this town. There are a few Digimon here to recruit, Metal Mamemon is a random encounter and the others are part of this town's story events.
When you first arrive here you'll need to locate Numemon (in the sewers) and Andromon (in the control room). Speak with Numemon first then Andromon, you'll also want to talk with the guards one screen to the right of Andromon. Speak with the top guard and ask him about when the shift changes. If you don't see this dialogue go back to Numemon and Andromon and speak with them again.
Return to this screen at 12pm or 12am and the guards will be gone. From this point forward they're always gone regardless of what time it is. You'll find the Digimon that we need (Giromon) rampaging in a room in this new section of Factorial Town. There are also lots of items throughout this area so be sure to search thoroughly!
Once Giromon has been defeated you can return to Numemon and recruit him. Return to Andromon a second time too and he will give you new dialogue then ask you to come back in a day. If you meet the requirements I talk about below, Andromon will join your city too.
Numemon
Requirement: Defeat Giromon
In order to recruit Numemon you will need to complete the story objectives in this map that I talk about in the paragraphs above. Once you do everything we talk about above, Numemon will challenge you to a fight and join the city once he has been defeated.
Andromon & Giromon
Requirement: Recruited Numemon & Complete Factorial Town story. Have Item Shop, Clinic, Restaurant and Arena buildings in town
You'll be able to recruit Andromon after completing the main story elements of this map. I talk about all of this at the top of the page if you'd like a verbose write up. After recruiting Andromon return to the room where you battled Giromon and speak with him again, he will join your city as well.
Metal Mamemon
Requirement: N/A
You can find Metal Mamemon on the second screen of Factorial Town. When you enter from the sea go one screen east and he has a very-very low chance of spawning here each time you enter/exit the screen. This is an Ultimate Digimon so make sure you bring one that is capable of defeating him, otherwise it will just be an item spam fight.
Nanimon
Requirement: Recruit Numemon & Complete Factorial Town Story
Nanimon can be found in the Sewers a little bit north of where Numemon was earlier. Much like with all of the other Nanimon encounters, you will need to complete the story events in this map and then leave and return to find Nanimon.
If you'd like to learn more about Nanimon and the locations he is found check out my Nanimon Recruitment Guide for more information.
All Nanimon Locations
1. Ancient Dino Region in the same area as Meteormon.
2. Ogre Fortress, found in the boss room where we battled Ogremon.
3. Leomon's Ancestor's Cave in Drill Tunnel, search the area where you get the tablet.
4. Toy Town, in the boss room.
5. Factorial Town, in the sewers north of where Numemon is found.