Deriving the formula for derangements: $\text{Round}\left[\frac{n!}{e}\right]$
23701
I have a problem understanding the proof of Rencontres numbers (Derangements)
17754
Intuitive Understanding of the constant "$e$"
6100
Show that $\left|\frac{\alpha - \beta}{1-\bar{\alpha}\beta}\right| < 1$ when $|\alpha|,|\beta| < 1$
149355
find $\left( \frac{x}{x+y} \right)^{2007} + \left( \frac{y}{x+y} \right)^{2007}$
57459
How to correctly format (and align) a LaTeX proof?
52353
Bounding Euler's e by showing $2 \leq \left (1+ \frac{1}{n}\right)^n < 3$
14013
How to prove that $\lim \frac{1}{n} \sqrt[n]{(n+1)(n+2)... 2n} = \frac{4}{e}$
129170
Deriving the expectation of $[\hat X,\hat H]$
51869
Why does $\;\lim_{n\to \infty }\frac{n}{n!^{1/n}}=e$?
115915
How do you derive Fleming's left hand rule?
150626
General formula or a pattern for the $n$th derivatives of $e^{f(x)}$?
127291
Show that $\left( \frac{q}{p} \right) \equiv q^{(p-1) / 2} \mod p$, where $\left( \frac{q}{p} \right)$ is the Legendre Symbol
103310
Evaluation of the following expression
81505
Derangement of $n$ elements
75279
Reversing the $T(n) = \frac{n(n+1)}{2}$ formula
76685
Determine $\text{Aut}(S)$ where $S = \mathbb{Q}[x]/(x^2)$
98514
Prove by induction that the number of derangements of length $n$ is $D_n = (n-1)(D_{n-1}+D_{n-2}), n>2$