If $n^2+1$ people are lined up, there are $n+1$ whose heights are increasing or decreasing
90652
How long does a sequence need to be to be guaranteed to have a monotonic subsequence length k?
45454
Pairs of $(p,q)$ such that $p^2 + 1 = 2 q^2$?
73553
How is $a_n=(1+1/n)^n$ monotonically increasing and bounded by $3$?
80575
Arrange the following growth rates in increasing order: $O (n (\log n)^2), O (35^n), O(35n^2 + 11), O(1), O(n \log n)$
115244
Integer solutions of $m^2+(m+1)^2=n^4+(n+1)^4$
45037
Show $(2^m-1,2^n+1)=1$ if $m$ is odd
94923
Using the Pigeonhole Principle to show that $2$ of any $n+1$ numbers from $\{1,2,\ldots,2n\}$ sum to $2n+1$
39156
Concerning what is between two consecutive squares.
136274
$n! \leq \left( \frac{n+1}{2} \right)^n$ via induction
140977
Why $\bar{z_1}z_2+\bar{z_2}z_3+\bar{z_3}z_1 \in \mathbb R \iff z_1, z_2, z_3 \text{ are along the same line}$
147901
Show that, in a group of n people, everyone has the same number of friends if..
7466
How would I prove that if an integer $n>2$, then $\bar{z}=z^{n-1}$ has $n+1$ solutions
83784
Fixed Point of $x_{n+1}=i^{x_n}$
46102
Prove that $2^n +1$ in never a perfect cube
92175
Given $y_n=(1+\frac{1}{n})^{n+1}$ show that $\lbrace y_n \rbrace$ is a decreasing sequence
126297
A high school Olympiad problem
24572
Does $n \mid 2^{2^n+1}+1$ imply $n \mid 2^{2^{2^n+1}+1}+1$?