Hi ↑ stuart clark:,
Personally I have shall demonstrate, for example, more generally that
for
, n natural number.
Skrytý text:A possible proof.
The formula of Mac Laurin one

for

,

real positive is:

We notice that all the terms in this formula are positive, so

and

give

Finally

For

in the last formula we obtain the answer to the question asked in
↑ stuart clark: Remark. There is several of the other elementary proofs without the formula of Stirling.