List questions from combinatorics | MathQA

Let $k,n$ be integers with $2\leq k \leq n$, consider set $S = \{1,2,...,n\}$. What is the #of $k$-element subsets $S$ that do not contain $1$ and $2$

Published on 16 Apr 2026 - 11:19

Combinatorics question involving distributing 9 different candies to three different kids

Published on 11 May 2026 - 6:37

Counting Help: What is the minimum number of employees such that we can guarantee that at least two of them have the same employee number?

Published on 17 Apr 2026 - 13:41

Purchasing Donuts

Published on 12 Apr 2026 - 7:58

maximum number of perfect matchings of $K_{2n}$ such that no edge appears in two different matchings

Published on 16 Apr 2026 - 17:03

Combinatorics question involving distributing DISTINCT candies to DISTINCT children

Published on 13 Apr 2026 - 15:11

How many half-squares can cover a square?

Published on 16 Apr 2026 - 1:54

A Combinatorics Problem: Where Did I Go Wrong?

Published on 13 Apr 2026 - 12:45

No. of ways to put 1's in exactly K cell of 2*N grid such that no two 1's cell share adjacent side

Published on 15 Apr 2026 - 17:43

How many natural numbers less than 2017 are there such that the summation of the digits of the number is 5?

Published on 16 Apr 2026 - 2:13

Calculate coefficient $z^n u^j$ of power series in two variables

Published on 14 Apr 2026 - 20:05

How To Tell When Order Matters Or Not

Published on 10 Apr 2026 - 7:48

what is the number of ways to split k distinct items into n distinct bins with no bin with exactly one item?

Published on 11 Apr 2026 - 21:32

does there exist an integer $m>1$ such that $a+m$ is a divisor of $a^m+1$?

Published on 06 May 2026 - 11:29

How many positive divisors of 2000?

Published on 09 Apr 2026 - 17:38