Intereting Posts

Sum of $\sum \limits_{n=0}^{\infty} \frac{1}{(kn)!}$
Determine the Winding Numbers of the Chinese Unicom Symbol
Proof by Strong Induction: $n = 2^a b,\, b\,$ odd, every natural a product of an odd and a power of 2
Gradient operator the adjoint of (minus) divergence operator?
Linear dependence of $\left\{x^{n}\,\colon\, n\in\mathbb{N}\right\}$
Inductive proof that ${2n\choose n}=\sum{n\choose i}^2.$
A funtion and its fourier transformation cannot both be compactly supported unless f=0
organize 5 subjects in 6 periods
Division polynomials of elliptic curves
Integers expressible in the form $x^2 + 3y^2$
Measure on Hilbert Space
Approximation of Shannon entropy by trigonometric functions
Prove that:$\int_{0}^{1}{x+x^2+\cdots+x^{2n}-2nx\over (1+x)\ln{x}}dx=\ln{\left}$
Seeking a layman's guide to Measure Theory
How to evaluate $\int_0^\infty \frac{1}{x^n+1} dx$

What is the **maximum** number of points that can be chosen from an $N$ by $N$ grid such that no $4$ of the chosen points form a rectangle with sides parallel to the axes of the grid?

Equivalently, what is the minimum number of points chosen from an $N$ by $N$ grid to guarantee a rectangle?

What if we remove also rule out rectangles with sides not parallel to the axes of the grid?

- How many planar arrangements of $n$ circles?
- minimum lines, maximum points
- Tiling problem: 100 by 100 grid and 1 by 8 pieces
- An Olympiad Problem (tiling a rectangle with the L-tetromino)
- square cake with raisins
- Maximum distance between points in a triangle

- $p$-Splittable Integers
- Proving identity $ \binom{n}{k} = (-1)^k \binom{k-n-1}{k} $. How to interpret factorials and binomial coefficients with negative integers.
- Weak $k$-compositions with each part less than $j$
- How many ways there are?
- How many $N$ digits binary numbers can be formed where $0$ is not repeated
- Can we solve this using stars and bars?
- How many ways can 70 planes be allocated into 4 runways?
- Why is a general formula for Kostka numbers “unlikely” to exist?
- A question related to the card game “Set”
- Probability/Combinatorics Problem. A closet containing n pairs of shoes.

- Showing that a ring is a field as well for one of the provided choices.
- Clarification on optimization problem
- Derivative of $f(x) \cdot g(x)^{(n)} = \sum_{k = 0}^{n}(-1)^k \cdot {n \choose k}\cdot (f(x)^{(k)}\cdot g(x))^{(n-k)}$
- is uniform convergent sequence leads to bounded function?
- How to show set of all bounded, analytic function forms a Banach space?
- Proof of linear independence of $e^{at}$
- Longest sequence of minimally finer topologies
- Race Problem counting
- How to count different card combinations with isomorphism?
- Evaluating $\int\limits_0^\infty \! \frac{x^{1/n}}{1+x^2} \ \mathrm{d}x$
- Is any permutation the product of two involutions?
- Covectors and Vectors
- A tough series related with a hypergeometric function with quarter integer parameters
- How do you calculate this limit without using L'Hopital or Taylor?
- Proving a sequence defined by a recurrence relation converges