New posts in combinatorics

How to generate permutations of a list without "reverse duplicates" in Python using generators

python algorithm generator combinatorics

How many ways are there to place $7$ people to $10$ seats around a circular table so that Alex and Bob in these $7$ people do not sit together?

combinatorics solution-verification permutations contest-math

How many four-digit positive integers are there that contain the digit $3$ and are divisible by $5$?

combinatorics algebra-precalculus solution-verification

Show that this structure is an affinely regular polygon

combinatorics geometry discrete-mathematics

Fundamental principle of counting in bench seating choice preferences in a subway

N gunmen in a field

combinatorics geometry contest-math extremal-combinatorics

In how many ways five distinct balls can be put into the boxes if each box can hold at most one ball and no two boxes without balls are adjacent?

Combinatorial proof

combinatorics analysis

ways of selecting consecutive persons sitting at a table

combinatorics combinations

How many three digit numbers are not divisible by 3, 5 or 11?

combinatorics discrete-mathematics divisibility

Finding coefficient of polynomial?

combinatorics functions polynomials binomial-coefficients

6 Heads Followed by 6 Tails (Coin Flipping)

probability combinatorics probability-theory probability-distributions recreational-mathematics

$\sum_{i=k}^{z} \frac{(-1)^{i-k} {z\choose i}{i\choose k}}{i+1} = \frac{1}{z+1} $ - combinatorial identity

integration combinatorics combinatorial-proofs

Why am I under-counting when calculating the probability of a full house?

probability combinatorics discrete-mathematics

Nested summations and their relation to binomial coefficients

combinatorics summation

Number of triangles in a regular polygon

combinatorics polygons

combinatorial answer using inclusion exclusion principles

combinatorics discrete-mathematics proof-verification inclusion-exclusion

In how many ways can n identical balls be distributed in three green, yellow and blue colored baskets?

Ways to select $m$ disjoint groups of consecutive elements from an $n$-element set

How to prove $\left \lceil \frac{n}{m} \right \rceil = \left \lfloor \frac{n+m-1}{m} \right \rfloor$?

combinatorics discrete-mathematics ceiling-and-floor-functions