New posts in Discrete Mathematics

Prove that for any integer $n>0$ which is a perfect square, $n+4$ is not a perfect square.

Let T be a tree such that every leaf is adjacent to a vertex of degree at least 3. Show that there are two leaves with a common neighbor.

Spanning tree created with cycles breaking different form the Maximal Spanning Tree.

Divisibility by 7 Proof by Induction

Permutations of race positions

Prove a graph is cyclic

$i+j-1$ tokens on row $i$ column $j$ of square grid

How many rectangles can be found in this shape?

How many $k$-letter words are there such that the letters A and B are not next to each other?

5 digit numbers from 1 3 3 0 0