I've not seen one coach come with a sewer hose from the factory (except for high-end coaches with a built-in macerator system that use a much smaller hose and special adapter). The only way you would get one is if the dealer gave you one as part of your deal.
You are also going to want more than one because not every campsite is configured so that one 10' hose will work all the time. I actually carry four 10' hoses.
Those types of items - - hoses, electric adapters, etc. - - are usually up to the buyer to purchase, although some dealers will include a "starter package" that includes such items and things like toilet paper, black tank chemicals, etc.
In most cases whatever starter kit the dealer may have "thrown in" will the absolute cheapest stuff on the market & if used frequently might last your 1st camping season.
I finally found a video (actually 2) where they showed the special sewer hose to use with the Sequence / Tellaro. It has a very tight end, and WAS made by Thetford, but is now obsolete. It is a 17730. Odd thing is that I can not find one less than 15', which would not collapse into the hole.
Mystery solved.