Number of elements not equal to their inverses is even number
67554
In a group, the number of non-self-inverse elements is even
17059
A ring element with a left inverse but no right inverse?
44745
How many positive integers less than 1000 have distinct digits and are even?
151508
How to determine number with same amount of odd and even divisors
156242
As many even numbers as natural numbers.
102136
How many subsets contain no consecutive elements?
153969
The "elements" of a real number
55840
Number of functions from n-element set to {1, 2, …, m}
151029
The number of non normal subgroups of a group cannot be $1$?
155372
Find the number of permutations in $S_n$ containing fixed elements in one cycle
75229
Can there be a function that's even and odd at the same time?
1576
Finding the elements in the group of units of the ring of integers modulo n that are their own inverse.
100565
Property of sup of a set of numbers
50133
The sum of odd powered real numbers equals zero implies the numbers are inverses
128834
Proving the number of even and odd permutations of a subgroup $H<S_{n}$ are equal, provided $H$ is not contained in $A_{n}$
9411
Number of permutations of $n$ elements where no number $i$ is in position $i$
142038
Finding the number of elements of order two in the symmetric group $S_4$