Questions tagged [prime-factorization]
For questions about factoring elements of rings into primes, or about the specific case of factoring natural numbers into primes.
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Prove that the set of positive rational numbers is countable
While I was studying Discrete Mathematics, I faced a question that I do not understand how to solve even after looking at the answer. The question asks me to prove that the set of positive rational ...
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What is the rate of increase in magnitude of a sorted list of factors of a large integer
I understand that the Hardy-Ramanujan theorum shows that a very large integer $n$ will on average have about $log(log(n))$ distinct factors. What I am interested in is how the magitude of the factors ...
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Distribution of perfect numbers for a semiprime
Given a semiprime with a length of 120 digits (397bit):
is it possible to meet any assumptions about perfect numbers (prime factors with same length, 199+199bit) for this number?
I have made an ...
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How to describe integers with the same prime factors?
Is there a term for the relationship between two integers that have the same prime factors? For example, $6=(2)(3)$ and $12=(2)(2)(3)$. Can one describe this with something along the lines of "$...
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Two questions around some new card game based on prime factorization.
I have been developing a card game called "Infinity", which involves a unique play mechanic based on card interactions. In this game, each card displays a set of symbols, and players match ...
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Factorizations not sharing digits with original number
The sequence A371862 is "Positive integers that can be written as the product of two or more other integers, none of which uses any of the digits in the number itself."
In the extended ...
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prime factorization in $\mathbb{Z}[i]$ [duplicate]
We were asked to show where the following reasoning goes wrong. Since $1+i$ and $1-i$ are prime elements in $\mathbb{Z}[i]$, the equation $$(-i)(1+i)^2=(1+i)(1-i)=2$$ show that unique prime ...
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Minimum $k$ for which every positive integer of the interval $(kn, (k+1)n)$ is divisible by at least one prime number less than $n$
As a continuation of this question relating the Minimum $k$ for which every positive integer of the interval $(kn, (k+1)n)$ is composite and this other one on the divisibility of numbers in intervals ...
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Prime factor wanted of the huge number $\sum_{j=1}^{10} j!^{j!}$
What is the smallest prime factor of $$\sum_{j=1}^{10} j!^{j!}$$ ?
Trial :
This number has $23\ 804\ 069$ digits , so if it were prime it would be a record prime. I do not think however that this ...
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Approximating a rational number in a subset of Q defined by limited prime factors
I'm wondering if there is an efficient (or good enough for small numbers) algorithm for the following problem:
Suppose I have a rational number in the form of its prime factorization:
$k = p_0^{x_0}...
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Divisibility of numbers in intervals of the form $[kn,(k+1)n]$ [duplicate]
I have checked that the following conjecture seems to be true:
There exists no interval of the form $[kn, (k+1)n]$ where each of the integers of the interval is divisible by at least one of the ...
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Question about sum of indices of prime factorisation of consecutive numbers that might be solved via Chinese remainder theorem? [duplicate]
Consider a set of (not necessarily consecutive) prime numbers, $S: = \{ p_1, p_2, \ldots, p_k\}.\ $ For each integer $n,$ for each $1\leq j \leq k,$ let (the function) $u_n(p_j)$ be the greatest ...
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Factorizaton in an Euclidean ring
I have a doubt concerning Lemma 3.7.4 from Topics in Algebra by I. N. Herstein.
The statement of the Lemma is:
Let $R$ be a Euclidean ring. Then every element in $R$ is either a unit in $R$ or can be ...
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Understanding the upper bound implications of $R(p,n) \le \log_p n$ in the context of Wikipedia's proof of Bertrand's Postulate
In Wikipedia's proof of Bertrand's Postulate, in the second lemma, it is concluded that:
$$R = R(p,{{2n}\choose{n}}) \le \log_p 2n$$
where $R(p,n)$ is the p-adic order of ${2n}\choose{n}$
Later in the ...
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Understanding an application of Legendre's Formula as used in the proof of Bertrand's Postulate
In Wikipedia's proof of Bertrand's Postulate, Legendre's Formula is used to establish an upper bound to the p-adic valuation of ${2n}\choose{n}$
The argument is presented as this:
(1) Let $R(p, x)$ ...
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