Newbetuts

Disproving the claim that the numbers 1+2+4, 1+2+4+8, 1+2+4+8+16... alternate between prime and composite

How many three digit numbers are not divisible by 3, 5 or 11?

Prove that either $m$ divides $n$ or $n$ divides $m$ given that $\operatorname{lcm}(m,n) + \operatorname{gcd}(m,n) = m + n$?

Prove that $gcd((a^{n}-b^{n})/(a-b), a-b) = gcd(n(a,b)^{n-1}, a-b)$ for a,b $\in$ $\mathbb{Z}^+$ [duplicate]

Prove the $n$th Fibonacci number is the integer closest to $\frac{1}{\sqrt{5}}\left( \frac{1 + \sqrt{5}}{2} \right)^n$

Prove that 17 divides 1111111111111111 (16 1's) and doesn't divide 11111111

Prove that $x$ and $x+1$ are coprime numbers

Prove by induction that $n^3 + 11n$ is divisible by $6$ for every positive integer $n$.

How many numbers can be divided by 7? [closed]

If $\gcd (x,4) = 2$ and $\gcd(y,4) = 2$ then $\gcd(x+y,4) = 4$

All numbers of form $10^{k} + 1$ are composite for $k{\gt}2$ proof

How to solve the equation $n^2 \equiv 0 \pmod{584}$?

$f'/f\in\mathbb{Z}[[x]]$ for polynomials vs. formal power series $f$

Proof that $\mathbb{Z}$ has no zero divisors

Reasons why division by zero is not infinity or it is infinity.

Prove by mathematical induction that $2^{3^n}+1$ is divisible by $3^{n+1}$

Does there always exist an even $m$ that is a multiple of exactly $n$ of the numbers $1$, $2$, ..., $2n$?

New posts in divisibility

Proof that a number evenly divides the difference of two numbers to the nth power

GCD in Gaussian integers.

Is "divisible by 15" the same as "divisible by 5 and divisible by 3"?

Disproving the claim that the numbers 1+2+4, 1+2+4+8, 1+2+4+8+16... alternate between prime and composite

How many three digit numbers are not divisible by 3, 5 or 11?

Prove that either $m$ divides $n$ or $n$ divides $m$ given that $\operatorname{lcm}(m,n) + \operatorname{gcd}(m,n) = m + n$?

Prove that $gcd((a^{n}-b^{n})/(a-b), a-b) = gcd(n(a,b)^{n-1}, a-b)$ for a,b $\in$ $\mathbb{Z}^+$ [duplicate]

Prove the $n$th Fibonacci number is the integer closest to $\frac{1}{\sqrt{5}}\left( \frac{1 + \sqrt{5}}{2} \right)^n$

Prove that 17 divides 1111111111111111 (16 1's) and doesn't divide 11111111

Prove that $x$ and $x+1$ are coprime numbers

Prove by induction that $n^3 + 11n$ is divisible by $6$ for every positive integer $n$.

How many numbers can be divided by 7? [closed]

If $\gcd (x,4) = 2$ and $\gcd(y,4) = 2$ then $\gcd(x+y,4) = 4$

All numbers of form $10^{k} + 1$ are composite for $k{\gt}2$ proof

How to solve the equation $n^2 \equiv 0 \pmod{584}$?

$f'/f\in\mathbb{Z}[[x]]$ for polynomials vs. formal power series $f$

Proof that $\mathbb{Z}$ has no zero divisors

Reasons why division by zero is not infinity or it is infinity.

Prove by mathematical induction that $2^{3^n}+1$ is divisible by $3^{n+1}$

Does there always exist an even $m$ that is a multiple of exactly $n$ of the numbers $1$, $2$, ..., $2n$?