All Questions
Tagged with nt.number-theory factorization
129 questions
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What upper bounds are known, for the number of divisors of Mersenne numbers?
Short version. What upper bounds are known, for the number of divisors of Mersenne numbers?
Long version.
Studying the structure of the factors of $M_n = 2^n - 1$ appears to be an active and difficult ...
- 1,424
1
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1
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176
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+50
On a probabilistic integer factorization algorithm given bounds for one prime factor
We got a probabilistic integer factorization algorithm and experimental evidence with large
integers given bounds for one factor.
Let $D \ge 2$ be real number and let $p,q$ be primes and $N=pq$.
...
- 25.4k
1
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0
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29
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Factoring semiprimes via sum of two squares? [migrated]
The following thoughts came into my head after watching Grant Sanderson's JBPM award lecture here, in which he discusses the fact that we can quickly factor 3599 by noticing it can be written as (60-1)...
- 61
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78
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Factoring totient of a prime
Is it any easy to factor $p-1$ when $p$ is a prime compared to general factorization problem?
What about when $2p+1$ is also a prime?
- 13.9k
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How dense are quotients of smooth numbers?
As usual, call a positive integer $y$-smooth if it has no prime factors greater than $y$. Write $S(x,y)$ for the set of $y$-smooth integers $\leq x$. Write $R(x,y)$ for the set of quotients $\{a/b: a,...
- 20.2k
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270
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How dense are (very but not extremely) smooth numbers? Can they be found in most (not very) short intervals?
An integer is said to be $y$-smooth if it has no prime factors $>y$. Let $y$ be "medium sized", meaning $(\log x)^{1+\epsilon} < y < \exp((\log x)^{2/3})$ or so. (Why this range of ...
- 20.2k
1
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60
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On the parity of $(2^{\varphi(n)}-1) \bmod{n^2}$
For odd integer $n$ define the function
$$ J(n)=(2^{\varphi(n)}-1) \bmod{n^2}$$
$J(n)$ is integer in $[0,n^2-1]$ and it is divisible by $n$.
Integer $n$ is Wieferich number
iff $J(n)=0$ and if $n$ is ...
- 25.4k
2
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1
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132
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On an integer factoring algorithm based on smooth class number of quadratic fields
We got an algorithm and toy implementation of integer factoring algorithm
based on smooth class number of quadratic fields.
It is close to the elliptic curve factorization method (ECM) and
succeeds if ...
- 25.4k
3
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1
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261
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Could efficient solutions of $x^2+n y^2=A$ be related to integer factorization?
Let $n$ be positive integer with unknown factorization and $A$ integer with known
factorization.
According to pari/gp developers pari can efficiently find all solutions of:
$$x^2+n y^2=A \qquad (1)$$
...
- 25.4k
2
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1
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161
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Fixed $a_p=p+1-\#E(\mathbb{F}_p)$ and $a_p \ne 0$ on an elliptic curve infinitely often for fixed curve over the rationals?
In this and this question we show that if $p=27a^2+27a+7$ is prime, then the order of the elliptic curve
$y^2=x^3+2$ modulo $p$ is either $p$ or $p+2$.
Q1 Can we unconditionally show that the order ...
- 25.4k
1
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0
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99
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$F(x,y)$ absolutely irreducible over the rationals, but reducible modulo infinitely many primes? [duplicate]
In this two page note we give efficient probabilistic algorithm for factoring bivariate
polynomials in composite characteristic assuming the solution is unique
and we would like to test the algorithm ...
- 25.4k
2
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1
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134
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On a efficient algorithm for factoring bivariate polynomials modulo composite modulus assuming the solution is unique
We found and implemented in sage efficient algorithm for factoring
bivariate polynomials modulo composite modulus assuming the solution is unique up to a constant factor.
More formally let $K=\mathbb{...
- 25.4k
13
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2
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596
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Number of distinct exponent patterns in the prime power factorizations of the integers 1,2,...,n
Let $n=p_1^{a_1}\cdots p_k^{a_k}$ be the prime power factorization of
the positive integer $n$, with $p_1<\cdots<p_k$ and $a_i>0$. Define
$\kappa(n)=(a_1,\dots,a_k)$, the composition type of $...
- 50.8k
1
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0
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128
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Effective Erdős–Kac theorem
I have some number $N$ and some integer $k>0$. I want to know what fraction of numbers up to $N$ have more than $k$ prime factors. (In my application, with repetition, but the $\omega$ version is ...
- 9,114
0
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1
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177
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Coefficients of 0,1-polynomials factorization
Let $n\in\mathbb{N}$ and $P_{n}$ is $0,1$-polynomial whose coefficients are binary digits of $n$.
Let $Q_{1}(x) \cdot Q_{2}(x) \cdots Q_{m}(x)$ - polynomial factorization (over integers) of $P_{n}$.
...
- 512
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1
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219
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Simple question about 0,1-polynomials
Being interested in these polynomials, would like to clarify one small observation.
Let $n\in\mathbb{N}$ and $P_{n}$ is $0,1$-polynomial whose coefficients are binary digits of $n$.
Let $n$ has prime ...
- 512
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79
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On the multiplicative group of quotients of polynomial rings
Related to this.
The $p+1$ factorization algorithm works over $\mathbb{Z}/n\mathbb{Z}[x]/f(x)$
and hopes $p+1$ to be smooth.
We are trying to generalize this to multivariate case
and also try to find ...
- 25.4k
3
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1
answer
82
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Evaluating the generalized continued fraction obtained from the factorization of a bivariate polynomial equation
Happy New Year, MO community!
We need someone expert in Generalized Continued Fractions (GCFs), with a deep knowledge of the GCFs’ convergence properties, to solve the following problem.
PROBLEM
...
- 125
3
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3
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382
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Closed formula for number of ones in a proper factor tree
Edit [2023 Dec 7]: One of my specific wonders, along with that of students, is around when a recursive formula might have – or be expected to have – an explicit or closed formula. What is the ...
- 7,831
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2
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328
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A doubt regarding the extended form of the Weierstrass factorization theorem
I want to represent $\sin(x)-\dfrac{1}{\sqrt{2}}$ as a product of it's zeroes
According to the Weierstrass factorization theorem, the sine function can be represented as a product of its factors:
$$\...
- 103
2
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0
answers
191
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Factorization of the polynomial $x^k + x^{k-1} + x^{k-2} + \cdots + x + 1$ in $\mathbb{F}_2[x]$ [closed]
Is anything known about the factorization of the polynomial $x^k + x^{k-1} + x^{k-2} + \cdots + x + 1$ in $\mathbb{F}_2[x]$?
When can it be factored, what are the irreducible factors, what are the ...
- 219
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0
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169
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$p^2+a^2$ can be a squarefree number with all prime divisors less than $p$?
Let $p$ be a prime $\ge 31$.
Is there an integer $a < p$ such that $p^2 + a^2$ is a squarefree and all of its prime divisors are less than $p$?
For example, for $p=31$, $31^2+5^2 = 986 = 2 \times ...
- 483
2
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1
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536
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Modular square roots problem which is $NP$ hard
It is well known extracting modular square roots modulo a composite number factors the modulus.
On other hand given $u,v>0$ and an integer $n$, deciding if there is a factor of $n$ in $[u,v]$ is $...
- 13.9k
2
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70
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Twin prime distribution centering twice a semiprime
What is the conjectured distributional behavior of semiprimes $pq$ ($p$ and $q$ are primes) having the property $2pq+1$ and $2pq-1$ are primes?
- 13.9k
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Distribution of number of prime factors of $p^k\pm1$
What is the behavior of number of prime factors of integers of form $p^k\pm1$ where $p$ is a fixed odd prime or $2$ and $k$ varies over positive integers?
- 13.9k
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70
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Is this factorization problem in EXP?
Factorization is not known to have a polynomial time algorithm. Traditionally the input length is number of bits in representation of the integer to be factored.
However now consider integers of form $...
- 13.9k
1
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138
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What are the limitations for calculating the inverse of a polynomial with the Lagrange inversion theorem?
I have been attempting to produce a series expression for the roots of high degree polynomial using the Lagrange Inversion theorem. I am curious about the statement from the Wikipedia page on Bring ...
- 547
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107
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Polynomial divisible by unbounded primes with exponent one
Let $f(x)$ be squarefree polynomial with integer coefficients and
degree at least $3$.
Is it true that for all sufficiently large $n$, $f(n)$ is divisible
by prime $p$ with exponent one and $p$ is ...
- 25.4k
1
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1
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181
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On the sequence $a(n)=\gcd(2^n-1,\phi(2^n-1))$
For natural $n$, define the sequence
$$
a(n)=\gcd(2^n-1,\phi(2^n-1))
$$
It doesn't appear to be in OEIS and starts
$1,1,1,1,9,1,1,1,3,1,9,1,3,1,1,1,27,1,75,49$
Q1 Can we unconditionally prove $a(n)=1$...
- 25.4k
2
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1
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514
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Eisenstein polynomial of totally ramified extension over $p$-adic field
Let $p\geq 3$ be a prime number, $K$ be a finite extension of $\mathbb{Q}_p$ with no non-trivial unramified subextension, $f(x)$ be an irreducible monic polynomial in $\mathcal{O}_K[x]$, making $L=K[x]...
- 549
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1
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315
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Fixpoints of $m\longmapsto \mathrm{rad}(\phi(m^2))$ under iteration
Given a strictly positive integer $m$ let $\alpha(m)=\mathrm{rad}(m\phi(m))$
be the radical (product of all distinct prime divisors) of the product of $m$ and of Euler's totient function $\phi(m)=m\...
- 17.9k
4
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1
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204
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Groups suitable for algebraic group factorizations of integers
Quoting Wikipedia on Algebraic-group factorisation algorithm
Algebraic-group factorisation algorithms are algorithms for factoring an integer N by working in an algebraic group defined modulo N whose ...
- 25.4k
5
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160
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Reducibility of $f(x)^{2^n}+1$ and $f(x)^{2^n}+g(x)^{2^n}$
Related to generalized Fermat numbers.
Let $f(x),g(x)$ be coprime polynomials with integer coefficients.
Assume that if $f(x)$ or $g(x)$ are of the form $h(x)^k$ then $k$ is power
of two.
Q1 Is it ...
- 25.4k
2
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0
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140
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Integers with exactly three factor pairs whose successors are relatively prime
I am interested in the following problem, and will appreciate pointers around how it can be solved – partially or fully – and/or indicators around whether it is even tractable:
Characterize $N \in \...
- 7,831
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Hensel's lemma, Bezout's identity, and the integers
Factorization in the ring $\mathbb{Z}[x]/(x^2+1)\mathbb{Z}[x]\cong \mathbb{Z}[i]$ is well known. For instance, $5$ and $13$ (and any prime $\equiv 1\pmod{4}$) are no longer prime.
The factorization ...
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360
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Positive divisors of $P(x,n)=1+x+x^2+ \cdots + x^n$ that are congruent to $1$ modulo $x$
This is a follow-up question to Positive integer solutions to the diophantine equation $(xz+1)(yz+1)=z^4+z^3 +z^2 +z+1$
Let \begin{equation}
P(x,n)= 1+x+x^2+ \cdots + x^n, \end{equation}
\begin{...
- 319
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138
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A diophantine equation involving partial sums of exponentials similar than the equation in Fermat's Last Theorem
I'm curious about the following diophantine equation from my invention: I don't know if this is in the literature, I wrote it using creativity in an attempt to write a variant of the equation in ...
1
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0
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178
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Need help interpreting this formula for the number of Goldbach partitions [closed]
1: Formula for the number of Goldbach partitions.
Let $g\left(n\right)$ denote the number of Goldbach partitions of even integer $2n$:
$$g_{\left(n\right)}=\sum_{3\leq p\leq2n-3}\left[\pi\left(2n-p\...
- 197
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1
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325
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Numbers with large prime exponents and the ABC conjecture
By Fermat's Last Theorem, there are no solutions to the Diophantine equation $a^n + b^n = c^n$ for $a,b,c > 0$ and $n>2$. Beal's conjecture allows the exponents to be different (but also $>...
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When $p(x)^2 \mid f(g(x))$?
Let $f(x),g(x),p(x)$ be non-constant polynomials with rational coefficients.
Is it true that for all $f$ exist $g,p$ such that $p(x)^2 \mid f(g(x))$?
Partial results:
$f(g(x))$ is divisible by square ...
- 25.4k
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4
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1k
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The smallest solution to $2^{2k}-1=\text{powerful}$
Integer is powerful if all the exponents in its factorization are at least $2$.
Every powerful integer can be written in the form $a^2 b^3$.
For odd $k$, define $F(k)=2^{2k}-1=(2^k-1)(2^k+1)$.
This ...
- 25.4k
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2
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804
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Must Mersenne numbers be divisible by arbitrary large primes with exponent one?
Let $M_n$ denote the Mersenne numbers $M_n=2^n-1$.
As $n$ varies, must $M_n$ be divisible by arbitrary large prime $p$
with exponent one, i.e. $p \mid M_n, p^2 \nmid M_n$?
In other words, must the ...
- 25.4k
2
votes
2
answers
405
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When is a prime factor of Mersenne number Wieferich prime?
Wieferich prime is a prime number $p$ such that $p^2$ divides $2^{p - 1} - 1$.
There are only two Wieferich primes known and it is an open problem if
there are infinitely many non-Wieferich primes.
...
- 25.4k
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0
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187
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Factoring integers of the form $n=p q^2$ using elliptic curves
We got argument and strong experimental support
that integers of the form $n=p q^2$ can
be factored using elliptic curves easier than general integers
Q1 Is this known?
Added This is known since at ...
- 25.4k
1
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0
answers
96
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Smooth number pairs satisfying a congruence
Let $\mathcal P=\{p_1,\dots,p_{2t}\}$ be $2t$ primes between $2^\ell$ and $2^{\ell+1}$ and fix an exponent bound $a\in\mathbb Z_{\geq2}$.
Fix $N\in\mathbb N$ whose prime factors $p$ satisfy $p>2^{\...
- 13.9k
2
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1
answer
262
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Are there any homomorphic analog error correction code?
Are there any analog error correction codes that are additively and multiplicatively homomorphic?
- 41
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110
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Evidence of optimality of sieve algorithms
Sieve techniques apply to integer factoring and discrete logarithm to provide $2^{O(((\log n)(\log\log n)^2)^{1/3})}$ complexity for $n$ bit factoring and $n$ bit prime discrete logarithm.
The state ...
- 13.9k
3
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0
answers
171
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The kronecker symbol and factorization of $n=\frac{B^N-1}{B-1}$
Let $n=\frac{B^N-1}{B-1}$. Assume $n$ is congruent to 3 modulo 4.
We have the following:
If $N$ is 1 modulo 4, then $N$ is quadratic residue modulo $n$
and $-N$ is quadratic non-residue. The square ...
- 25.4k
0
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0
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135
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Can factorization of very large numbers be aided by associating them with a series (described below) of quadratic polynomials?
My name is J. Calvin Smith. I graduated in 1979 with a Bachelor of Arts in Mathematics from Georgia College in Milledgeville, Georgia. My Federal career (1979-2012) in the US Department of Defense led ...
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2
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Updates on a least prime factor conjecture by Erdos
In the 1993 article "Estimates of the Least Prime Factor of a Binomial Coefficient," Erdos et al. conjectured that
$$\operatorname{lpf} {N \choose k} \leq \max(N/k,13)$$
With finitely many ...
