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2 votes
2 answers
144 views

Finding positive integer $n>10$ that maximizes $\frac{\sigma_0(n)}{2^{\log n}}$

Among all the positive integer, which one integer, $n$, can make the number below the largest? $$f(n)=\frac{\sigma_0(n)}{2^t}$$where $t=\log_{10}n$ and $\sigma_0$ is the divisor function. For example,...
A Math guy's user avatar
1 vote
4 answers
98 views

When $f(x)=\frac{-b^2m-ba+ax}{-mx-bm-a}$ is an integer

$a,b,m,x$ are positive integers. For which $x>0$ is $f(x)$ an integer? $$f(x)=\frac{-b^2m-ba+ax}{-mx-bm-a}$$ I been trying to play with it, I changed it to: $$\frac{b^2m-a\left(b+x\right)}{a+m\...
Ilya Gazman's user avatar
  • 1,450
1 vote
1 answer
73 views

When $f(x) = \frac{ax + b}{a -x + 1}$ is an integer

Given that $a$ and $b$ are positive integers. and $$f(x) = \frac{ax + b}{a -x + 1}$$ is an integer, what integer values can x have? If I could only somehow move $x$ from numerator to the denominator ...
Ilya Gazman's user avatar
  • 1,450
6 votes
2 answers
9k views

Total number of divisors of factorial of a number

I came across a problem of how to calculate total number of divisors of factorial of a number. I know that total number of divisor of a number $n= p_1^a p_2^b p_3^c $ is $(a+1)*(b+1)*(c+1)$ where $a,...
DCoder's user avatar
  • 298