I am trying to check whether or not the sequence an={nnn!}∞n=1
My best argument so far is as follows,
an=n⋅n⋅n⋅…⋅nn(n−1)(n−2)(n−3)…(2)(1)=nn⋅nn−1⋅…⋅n2⋅n
so liman→∞ since $n
This feels a little dubious to me, I feel like I can form a much better argument than that, or at the very least a more elegant one. I've tried to assume {an} approaches some limit L so there exists some N such that
|an−L|<ϵ whenever n>N and derive a contradiction, but this approach got me nowhere.
Finally, I've also tried to use the fact that an+1an→e to help me, but I couldn't find an argument where that fact would be useful.
Answer
HINT for the last part: Note that
an+1an=(n+1)n+1(n+1)!nnn!=(n+1)n+1n!nn(n+1)!=(n+1)n+1nn(n+1)=(n+1n)n.
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