[r-t] Cattermole

[Fred Bone]

On 01 September 2009 at 18:08, King, Peter R said:

> Can this be right? Is e here the basis of natural logs (2.718...)? If so
> this means the number of derangements is an irrational number rather than
> an integer. Surely this isn't correct. I think it is the nearest integer
> to n!/e. 

The limit as n tends to infinity of (n! / derangements(n)) is e.

As the number of derangements is obviously an integer, I thought it 
unnecessary to specify the rounding.