$n + 1$ numbers are picked at random from $2n$ integers $1, 2, 3,\dots , 2n$?
31890
Prove using induction that from a set of $n+1$ numbers from $\{1,2,..2n\}$, at least one number will evenly divide another.
153072
Guessing a subset of $\{1,...,N\}$
123117
Is it possible to find $n-1$ consecutive composite integers
34595
Generating non-repeating random numbers
76405
Let n be an even integer. How many different ways can I choose subsets of the set {1,2...,n}
110295
Probability that uniform random variables equal the natural numbers
68507
Random number generation and probability
103732
Proving that for $n \equiv 0 \pmod{2}$, we get ${n \choose 0} < {n \choose 1} <\ldots< {n \choose n/2-1}<{n\choose n/2}$ etc.
39005
Probability that a number has $m$ indistinct factors
54442
Sum of $k {n \choose k}$ is $n2^{n-1}$
151452
Random real numbers that sum up to specific value
45074
Combinatorics: Selecting objects arranged in a circle
21598
A game of guessing a chosen number
70282
Help finding a combinatorial proof of $k {n \choose k } = n {n - 1 \choose k -1}$
142534
Proof of $k {n\choose k} = n {n-1 \choose k-1}$ using direct proof
15002
Unique (non-repeating) random numbers in O(1)?
9411
Number of permutations of $n$ elements where no number $i$ is in position $i$