Wow! Derangements! A WINNER IS YOU, EXFRET!
Funny how this little puzzle points to a well researched (and well-defined) bit of mathematics. Now I need to sit down with it and try to understand *how* they got all those formulas. Thank goodness for both xkcd and wikipedia, eh?
A Puzzle
Re: A Puzzle
You said something about getting close to the answer.
Were you ever close to getting it? Did you even know what derangements were before?And this is the fun thing about the problem -- on its surface, it seems so simple. But my first few (okay, many) attempts at answering it also failed. There's always some extra challenge or exception that crops up. In fact, while I think I'm closer to an answer than before, I haven't been able to write down a complete formula yet.
Nobody ever notices my signature. ):