centaur

Tell me what it is, it is not mentioned in the Chessopedia.

engine assisted, Romy

Here's a discussion of a centaur tournament, so yes it's possible but I can't find anything official for you.

http://www.chess.com/forum/view/help-support/flagged-for-cheating-in-a-centaur-tournament

Look I'm no proponent of centaur chess, but come on, you've read the same threads I have.  It's not a matter of just plugging in the engine's move.  Centaur chess folks take the engine's moves under advisement but the best centaur players rely on human judgement to make the final call.  I don't particularly find it appealing myself, but I can see why some would.  Having a digital coach doesn't make the game a cut and dried affair by any means.  Eliminating blunders doesn't mean eliminating ambiguity.