16 questions linked to/from Fermat numbers are coprime
1k views

85 views

### Prove that $\gcd(g_a,g_b) = 1$ given that for $n \in Z^{\geq 0}$, define $g_n = 2^{2^n} + 1$ [duplicate]

Prove that $\gcd(g_a,g_b) = 1$ given that for $n \in Z^{\geq 0}$, define $g_n = 2^{2^n} + 1$. I have already proved that $g_0\cdot g_1\cdots g_{n-1} = g_n -2$ if this hint is useful in this proof.
96 views

### $(a^{2^n}+1,a^{2^m}+1)=1 or 2$ [duplicate]

Prove that if $m\not =n,a$ are positive integers then $(a^{2^n}+1,a^{2^m}+1)$ is $1$ if $a$ is even and $2$ if $a$ is odd. I solve the problem in the following way: I assume that $m>n$ then a^{...
65 views

### Problems regarding GCD [duplicate]

If $m > n$ and $a,m,n$ are positive, with $m$ not equal to $n$, find the greatest common divisor of $2^{2^m}+1, 2^{2^n}+1$. Please solve this problem using Euclid's algorithm. I tried to use ...
47 views

### Fermat Prime Numbers Coprime [duplicate]

Fermat numbers are shown by: $F_m = 2^{2^m} + 1$. How can I prove that for any $m ≠ n$, I can have $(F_m, F_n) = 1$, or coprime?
4k views

### Prove that distinct Fermat Numbers are relatively prime [duplicate]

The Fermat numbers are defined by $F_m = 2^{2^m} + 1$. Prove that for $m \ne n$ we have $(F_m, F_n) = 1$. I have to first prove that $F_{m+1} = F_0F_1 \cdots F_m + 2$ by representing $F_{m+1}$ in ...
187 views

### Show that Fermat number $F_n$ and its index $n$ are coprime.

I want to show that $\gcd(F_n,n)=1$, where $F_n=2^{2^n}+1$. How to prove this? I can show that that $\gcd(F_n, F_m)=1$ for any natural $n$ and $m$, and that $F_{n+1}=(F_n)^2-2F_n+2=F_0\dots F_{n-1}+2$...
309 views

### Co prime numbers

How to find a set of numbers which are coprime to each other (all numbers are pairwise co prime) ? the numbers can be assumed to be less than a specific integers. like all numbers in the range [0,x]
171 views

### Show that the only divisors are $1$ and $2$ for $(z^{(2^x)}+1)$ and $(z^{(2^y)}+1)$ where $x,y,z\in\mathbb{N}$
I am trying to show that the only divisors are $1$ and $2$ for both $(z^{(2^x)}+1)$ and $(z^{(2^y)}+1)$ where $x,y,z\in\mathbb{N}$. To start the problem, the logical choice is to use difference of ...