Intereting Posts

“Fair” game in Williams
Find a smooth function with prescribed moments
Showing a certain subspace of Hilbert space is dense
If the unit sphere of a normed space is homogeneous is the space an inner product space?
Calculation of the moments using Hypergeometric distribution
Is such a map always null-homotopic?
Laurent series for $1/(e^z-1)$
evaluating sum of limits
Gathering books on Lorentzian Geometry
Algebraic numbers that cannot be expressed using integers and elementary functions
Is cantor set homeomorphic to the unit interval?
Has there ever been an application of dividing by zero?
How many different numbers can be written if each used digit symbol is used at least 2 times?
If G is a group of order n=35, then it is cyclic
Show that $m\mathbb{Z}/md\mathbb{Z} \cong \mathbb{Z}/d\mathbb{Z}$ if and only if $(d,m)=1$

I came across with a problem where I was required to examine primality of $n! +1$ (17! + 1 was the actual number).

Although Wilson’s Theorem could be manipulated for determining primality of $n! + 1$ when $n + 1$ is a prime and $n! – 1$ when $n + 2$ is a prime, it does not cover the specific example that I am dealing with. Is there any formula (or a more generalized formula that covers the whole problem space) for determining primality of $n! +1$ when $n + 1$ is not a prime?

- Given number of trailing zeros in n!, find out the possible values of n.
- Is there an equivalent to the Bertrand's postulate between factorials and primorials?
- Finding $\lim_{n \to \infty} \frac{\sqrt{n!}}{2^n}$
- Use induction to prove the following: $1! + 2! + … + n! \le (n + 1)!$
- How can I calculate the limit of exponential divided by factorial?
- Finite Summation of Fractional Factorial Series

- Limits defined for negative factorials (i.e. $(-n)!,\space n\in\mathbb{N}$)
- Why is $\log(n!)$ $O(n\log n)$?
- Factorial sum estimate $\sum_{n=m+1}^\infty \frac{1}{n!} \le \frac{1}{m\cdot m!}$
- Show this equality (The factorial as an alternate sum with binomial coefficients).
- Summation of a series help: $\sum \frac{n-1}{n!}$
- When does a Square Matrix have an LU Decomposition?
- Double factorial series
- Is $\ 7!=5040\ $ the largest highly composite factorial?
- Proving $\sum_{k=1}^n k\cdot k! = (n+1)!-1$ without using mathematical Induction.
- What are the rules for factorial manipulation?

- explicit “exotic” charts
- Divisor in $\mathbb{C}$ $\implies$ divisor in $\mathbb{R}$?
- When is the weighted space $\ell^p(\mathbb{Z},\omega)$ a Banach algebra ($p>1$)?
- Number of 5 letter words with at least two consecutive letters same
- Is it mathematically wrong to prove the Intermediate Value Theorem informally?
- Prove an inequality
- Why the gradient of $\log{\det{X}}$ is $X^{-1}$, and where did trace tr() go??
- Euler-Mascheroni constant expression, further simplification
- Improper integral of $\sin^2(x)/x^2$ evaluated via residues
- How to show the curves are conics.
- How many resistors are needed?
- Every metric space can be isometrically embedded in a Banach space, so that it's a linearly independent set
- Find a general control and then show that this could have been achieved at x2
- Can forcing push the continuum above a weakly inacessible cardinal?
- Is it possible to make the set $M:=\{(x,y)\in\mathbb{R}^2:y=|x|\}$ into a differentiable manifold?