Divisibility if a is odd.
25825
Proof that $\gcd(ax+by,cx+dy)=\gcd(x,y)$ if $ad-bc= \pm 1$
97411
If $x^n=y^n$ and $n$ is odd then $x=y$
77816
Proof problem: Show that $n^2-1$ is divisible by $8$, if $n$ is an odd positive integer.
27889
If the set of odd numbers is a subset of $\mathbb N$ then surely it is smaller than $\mathbb N$
11967
number of subsets of even and odd
75723
Odd Binomial Coefficients?
40030
FA that accepts odd number of $b$ and even number of $a$
66703
Show that $8 \mid (a^2-b^2)$ for $a$ and $b$ both odd
116970
On the number divisors of a number
40565
How can I prove that one of $n$, $n+2$, and $n+4$ must be divisible by three, for any $n\in\mathbb{N}$
153892
Number Theory divisibilty
13525
Prove: If $n=2^k-1$, then $\binom{n}{i}$ is odd for $0\leq i\leq n$
117380
Divisibility Rule for 9
41295
Divisibility, LCM and GCD for fractions (rationals)
128377
Mathematical Induction and "the product of odd numbers is odd"
156641
Show that $\gcd(3n,3n+ 2) = 1$ when $n$ is odd
85272
$3x + 1$ is even iff $5x-2$ is odd