Permute numbers from 1 to n so that every number is in a different position
12487
Prove derangement formula by induction
98313
Number of possible permutations of n1 1's, n2 2's, n3 3's, n4 4's such that no two adjacent elements are same?
73206
recursion-consecutive numbers
27427
Arranging numbers from $1$ to $n$ such that the sum of every two adjacent numbers is a perfect power
75223
Generate all possible permutations (or n-tuples)
136885
Series of natural numbers which has all same digits
139350
Given two coprime integers, find multiples of them that differ by 1
15002
Unique (non-repeating) random numbers in O(1)?
9411
Number of permutations of $n$ elements where no number $i$ is in position $i$
48605
Distinct digits in a combination of 6 digits
73323
Permutations when some objects are alike
31478
Using bitwise OR 0 to floor a number
119292
How to generate all permutations of an array in sorted order?
77600
How to create a consecutive group number
91770
Python: order in a set of numbers
117898
Separate the alphabet and digit such that their relative order remains the same in O(n) time and O(1) space
67173
How to collapse consecutive numbers into ranges?