Questions tagged [perfect-powers]

A perfect power is a positive integer that can be expressed as an integer power of another positive integer. This tag should only be used when having in mind an arbitrary perfect power (as opposed to a specific one, like a perfect square, a perfect cube, etc.).

Questions about perfect powers, which are defined by:

A perfect power is a positive integer that can be expressed as an integer power of another positive integer.

This tag should only be used when having in mind an arbitrary perfect power (as opposed to a specific one, like a perfect square, perfect cube, etc.).

A related theorem is Catalan's Conjecture (now proved), stating that (given integers $x,y,a,b>1$)

$$x^y-a^b=1\iff (x,y,a,b)=(3,2,2,3)$$

Pillai's Conjecture is a conjecture that concerns whether every difference (not only $1$) of perfect powers occurs only finitely often.

315 questions
1
vote
1 answer

First decimal digit of a very large number.

Find the first digit (the left one) of the number $2016^{2016}$, not by actually compute it. I know the solution is 7, thanks to Wolfram Alpha's power, but I did not succeeded in finding it. Question number two: how may i calculate log values used…
Blumer
  • 600
  • 2
  • 12
0
votes
0 answers

Is there an analogue to Bertrand's Postulate for primes for perfect powers?

Is there an analogue to Bertrand's Postulate for primes for perfect powers? Bertrand's Postulate: $\forall x \gt 1 \in \mathbb{Z}, \exists p \in \mathbb{P}$ such that $x < p < 2x$. For perfect powers, could we say something like $\exists k,m,\lambda…
vvg
  • 3,311
0
votes
1 answer

Finding the smallest perfect power in a range

Given a range $[a, b]$, how does one find the smallest perfect power contained in the range? i.e., find $a \le k^m \le b$ where $a, b \in \mathbb{R_{\ge 0}}$ and $k, m \in \mathbb{Z_{\ge 0}}, m \ge 2$. If $N(x)$, is the counting function for perfect…
vvg
  • 3,311
0
votes
0 answers

Fixed point power function for fractional values

I am using below Matlab code to calculate power function i.e. without using built-in function. My requirement is - What improvement/ suggestion make the below function support fractional base and exponential values to calculate power? Thank you b =…
Coder
  • 1
0
votes
0 answers

How to find power of a given number?

65536= 4^8------( how can i find the base and power for a number.) Now, if I am randomly given a number. Say, 4096 and I need to find a common base having some power. I mean a^n. Where a is the base and n is its power. So, accordingly answer for…
0
votes
3 answers

How to find $m$ if $m+7$ & $m-34$ are both perefect squares?

Today I've got a math contest. And I couldn't solve the following problem : Let $m$ be a natural number, where : $m+7$ is a perfect square & $m-34$ is also a perfect square . What's the value of $m$ ? I have absolutely no idea on how should I…
DeltaWeb
  • 773
0
votes
3 answers

Determine if a positive integer $x$ is a product of a power of 2 and a power of 5. $f(x) = 2^n \cdot 5^n$

Determine if a positive integer $x$ is a product of a power of $2$ and a power of $5$. $f(x) = 2^m \cdot 5^n$ where $0 < x < 32$ and $0 < m < 32$ and $0 < n < 32$ This has to do with computational efficiency so I want to know if the decimal or…
Raheel Khan
  • 569
  • 1
  • 5
  • 21