update to A094047: arrangements of n couples

[Maximilian Hasler]

I'm sorry for using (maybe(?)) nonstandard terminology.
By semifactorial I mean what is called "double factorial" on OEIS,

http://www.research.att.com/~njas/sequences/A001147
 	 	 Double factorial numbers: (2n-1)!! = 1.3.5....(2n-1).

Maximilian

On Feb 11, 2008 8:47 AM, Maximilian Hasler <maximilian.hasler at gmail.com> wrote:
> When divided by the semifactorial, the "unlabelled cars" sequence equals
>
> http://www.research.att.com/~njas/sequences/A059072
> Penrice Christmas gift numbers; card-matching numbers; dinner-diner
> matching numbers.
>
> and (essentially the same)
>
> http://www.research.att.com/~njas/sequences/A000459
> Number of permutations with no hits on 2 main diagonals.
>
> Maximilian
>



-- 
Maximilian F. Hasler (Maximilian.Hasler(AT)gmail.com)