Some conjectures in elementary number theory, II (original) (raw)

Abstract factorials of arbitrary sets of integers

2007

A commutative semigroup of abstract factorials is defined in the context of the ring of integers. We study such factorials for their own sake, whether they are or are not connected to sets of integers. Given a subset X ⊆ Z + we construct a "factorial set" with which one may define a multitude of abstract factorials on X. We study the possible equality of consecutive factorials, a dichotomy involving the limit superior of the ratios of consecutive factorials and we provide many examples outlining the applications of the ensuing theory; examples dealing with prime numbers, Fibonacci numbers, and highly composite numbers among other sets of integers. One of our results states that given any abstract factorial the series of reciprocals of its factorials always converges to an irrational number. Thus, for example, for any positive integer k the series of the reciprocals of the k-th powers of the cumulative product of the divisors of the numbers from 1 to n is irrational. n j=1 σ k (j) ,

Abstract factorials

arXiv (Cornell University), 2007

A commutative semigroup of abstract factorials is defined in the context of the ring of integers. We study such factorials for their own sake, whether they are or are not connected to sets of integers. Given a subset X ⊆ Z + we construct a "factorial set" with which one may define a multitude of abstract factorials on X. We study the possible equality of consecutive factorials, a dichotomy involving the limit superior of the ratios of consecutive factorials and we provide many examples outlining the applications of the ensuing theory; examples dealing with prime numbers, Fibonacci numbers, and highly composite numbers among other sets of integers. One of our results states that given any abstract factorial the series of reciprocals of its factorials always converges to an irrational number. Thus, for example, for any positive integer k the series of the reciprocals of the k-th powers of the cumulative product of the divisors of the numbers from 1 to n is irrational. n j=1 σ k (j) ,

Abstract factorial functions and their applications

2007

A commutative semigroup of abstract factorials is defined in the context of the ring of integers. We study such factorials for their own sake, whether they are or are not connected to sets of integers. Given a subset X of the positive integers we construct a "factorial set" with which one may define a multitude of abstract factorials on X. We study the possible equality of consecutive factorials, a dichotomy involving the limit superior of the ratios of consecutive factorials and we provide many examples outlining the applications of the ensuing theory; examples dealing with prime numbers, Fibonacci numbers, and highly composite numbers among other sets of integers. One of our results states that given any abstract factorial the series of reciprocals of its factorials always converges to an irrational number. Thus, for example, for any positive integer k the series of the reciprocals of the k-th powers of the cumulative product of the divisors of the numbers from 1 to n is irrational.

Notes on Number Theory and Discrete Mathematics

2003

1. The Smarandache, Pseudo-Smarandache, resp. Smarandache-simple functions are defined as ([7J, [6]) S{n) = min{rn EN: nlm!}, Z(n) = min {m.E N: nl m{n~ + 1)} , 5p (n) = min{m EN: p"lm!} for fixed primes p. The duals of Sand Z have been studied e.g. in (2], [5J, [6]: 5.(n) = max{m EN: m!ln}, { m(rn+1) } Z.(n) = max mEN: 2

New Equivalents of Kurepa’s Hypothesis for Left Factorial

Axioms

Kurepa’s hypothesis for the left factorial has been an unsolved problem for more than 50 years. In this paper, we have proposed new equivalents for Kurepa’s hypothesis for the left factorial. The connection between the left factorial and the continued fractions is given. The new equivalent based on the properties of the integer part of real numbers is proven. Moreover, a new equivalent based on the properties of two well-known sequences is given. A new representation of the left factorial is listed. Since derangement numbers are closely related to Kurepa’s hypothesis, we made some notes about the derangement numbers and defined a new sequence of natural numbers based on the derangement numbers. In this paper, we indicate a possible direction for further research through solving quadratic equations.

Some conjectures in elementary number theory

2013

We announce a number of conjectures associated with and arising from a study of primes and irrationals in mathbbR\mathbb{R}mathbbR. All are supported by numerical verification to the extent possible.

The exponents in the prime decomposition of factorials

Archiv der Mathematik, 2016

Let νp(n) be the exponent of p in the prime decomposition of n. We show that for different primes p, q satisfying some mild constraints the integers νp(n!) and νq(n!) cannot both be of a rather special form.

On the Parity of Exponents in the Factorization ofn!

Journal of Number Theory, 1997

It is shown that, for any k, there exist infinitely many positive integers n such that in the prime power factorization of n!, all first k primes appear to even exponents. This answers a question of Erdo s and Graham (``Old and New Problems and Results in Combinatorial Number Theory,'' L'Enseignement Mathe matique, Imprimerie Kundia, Geneva, 1980). A few generalizations are provided as well. 1997 Academic Press Question. Does there exist, for every fixed k, some n>1 with all the exponents _ 1 (n), _ 2 (n), ..., _ k (n) even? Our first result answers this question in the affirmative.

On the decomposition of n! into primes

Abstract. In this note, we make explicit approximation of the average of prime powers in the decomposition of n!. Then we find the order of geometric and harmonic means of such powers. ... 1.1. Approximate Formula for the Function Υ(n). First, we note that integrating by