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Jun
7
comment How to generate a random number between 1 and 10 with a six-sided die?
.....Jack show!
Jun
6
comment How many integers $\{xy \colon 1\le x\le y\le 2x\}$?
The distribution of integers with a divisor in a given interval , Annals of Math. (2) 168 (2008), 367-433, Kevinf Ford [Corollary 3]: it is an atomic bomb, but yes it works, very thanks!
Jun
6
revised How many integers $\{xy \colon 1\le x\le y\le 2x\}$?
edited title
Jun
5
accepted Splitting the asymptotic upper density
Jun
5
asked Splitting the asymptotic upper density
Jun
4
accepted How many integers $\{xy \colon 1\le x\le y\le 2x\}$?
May
29
answered Find the sequence of partial sums for the series $a_n = (-1)^n$ Does this series converge?
May
19
comment Approximating $e^{x}/(e^{x} - 1)$
It depends where you'd like to approximate it ;)
May
18
asked How many integers $\{xy \colon 1\le x\le y\le 2x\}$?
May
6
revised Filtering a sum of reciprocal of integers
added 110 characters in body
May
6
accepted Only finitely many $a, b$ such that $2+3^n+5^{n^2}=2^a7^b$ for some $n$?
May
6
revised Filtering a sum of reciprocal of integers
added 14 characters in body; edited title
May
6
asked Filtering a sum of reciprocal of integers
May
2
comment Only finitely many $a, b$ such that $2+3^n+5^{n^2}=2^a7^b$ for some $n$?
If it is a solution for a fixed $n$, then it is exactly one: it is asked to prove that there exist only finitely many $n$ such that the dophantine equation has (a) solution..
May
2
answered Check the convergence of $a_{n+1}=\sqrt{a_n+\frac{4}{a_n}}$ where $a_1=4$
May
2
asked Only finitely many $a, b$ such that $2+3^n+5^{n^2}=2^a7^b$ for some $n$?
May
2
answered If $m, n$ be positive integers, prove that $\phi(mn)=\phi((m,n))\phi([m,n])$, where $(m,n)=$ gcd of $m, n$ and $[m, n]=$ lcm of $m, n$.
May
2
comment If $m, n$ be positive integers, prove that $\phi(mn)=\phi((m,n))\phi([m,n])$, where $(m,n)=$ gcd of $m, n$ and $[m, n]=$ lcm of $m, n$.
Oh I see now that (6,9) is not a counterexample for the new problem. Wait, I put it in a new answer
May
1
comment If $m, n$ be positive integers, prove that $\phi(mn)=\phi((m,n))\phi([m,n])$, where $(m,n)=$ gcd of $m, n$ and $[m, n]=$ lcm of $m, n$.
Indeed, he asks for $\varphi(m)\varphi(n)$, not $\varphi(mn)$ [recall that they are equal if and only if m and n are coprime, as expected..]
Apr
30
comment If $m, n$ be positive integers, prove that $\phi(mn)=\phi((m,n))\phi([m,n])$, where $(m,n)=$ gcd of $m, n$ and $[m, n]=$ lcm of $m, n$.
I have the fifth edition.. Can you check where is it exactly?