let M be a set of those natural numbers that can be written using only 0's and 1's
127843
Prove that, for any natural number $k$ $\exists m \in M $ s.t i) $m$ has exactly $k$ $1$'s, an
158257
Is aleph-$0$ a natural number?
40970
All the ternary n-words with an even sum of digits and a zero.
101751
The number of words that can be made by permuting the letters of _MATHEMATICS_ is
3217
Construction of uncountably many non-isomorphic linear (total) orderings of natural numbers
70327
the numer of partial function between two sets in combinatoric way
37783
Proving that a set of 2016 natural numbers contain a non-empty set with a sum divisible by 2016
12803
Proof for number of weak compositions
95287
Generating a list of numbers that are not multiples of 4
76434
What is the measure of the set of numbers in $[0,1]$ whose decimal expansions do not contain $5$?
96260
Number of occurrences of k consecutive 1's in a binary string of length n (containing only 1's and 0's)
132041
Numbers which cannot be formed
119982
how to express the set of natural numbers in ZFC
126015
Elementary number theory in sets
154459
Constructing a HoTT proof term of 1≠0
28579
Creating a sequence that does not have an increasing or a decreasing sequence of length 3 from a set with 5 elements
45392
Every natural number can be written as the sum of distinct Fibonacci numbers?