update to A094047: arrangements of n couples

[Maximilian Hasler]

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