Yes, there’s a recursive construction that converts a superpermutation of length...

Yes, there’s a recursive construction that converts a superpermutation of length l on n symbols to a superpermutation of length l + (n+1)! on (n+1) symbols.

The construction is described in various places online. I like Greg Egan’s description here: http://www.gregegan.net/SCIENCE/Superpermutations/Superpermu...

Sorry for the delayed reply. I was stymied by my aggressive noprocrast setting.