The set of natural numbers that don't belong to a set
104494
$m$ doesn't come in the sequence $a_n=[n+\sqrt{n}+\frac{1}{2}]$ iff m is a perfect square
116783
Simplicial sets which are not Kan complexes
47720
Isomorphism from Natural numbers to the Odd Natural numbers
83037
Applying Zorn's Lemma to natural numbers
3217
Construction of uncountably many non-isomorphic linear (total) orderings of natural numbers
33705
Is $0$ a natural number?
114770
Proof that a perfect set is uncountable
124115
Give an example of a set that has the set of natural numbers as it s set of accumulation points.
45788
$n$-th digit in the sequence of natural numbers
147428
Probability of picking an odd number from the set of naturals?
128766
Show that the set of functions $\mathbb{N}\to\{0,1\}$ is not countable
37783
Proving that a set of 2016 natural numbers contain a non-empty set with a sum divisible by 2016
146560
Is there any uncountably infinite set that does not generate the reals?
70196
Is there any well-ordered uncountable set of real numbers under the original ordering?
42603
How can I prove that the cadinality of a set minus a finite number of elements of it is still the same as the original set?
141299
Alternative set theories
71935
Let $k$ be a natural number . Then $3k+1$ , $4k+1$ and $6k+1$ cannot all be square numbers.