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Pantelimon Stanica

Publications and source records attributed to Pantelimon Stanica.

63 records · Page 4Linked to original sources

On the prime power factorization of n!

In this paper we prove two results. The first theorem uses a paper of Kim \cite{K} to show that for fixed primes $p_1,...,p_k$, and for fixed integers $m_1,...,m_k$, with $p_i\not|m_i$, the numbers $(e_{p_1}(n),...,e_{p_k}(n))$ are uniformly distributed modulo $(m_1,...,m_k)$, where $e_p(n)$ is the order of the prime $p$ in the factorization of $n!$. That implies one of Sander's conjecture from \cite{S}, for any set of odd primes. Berend \cite{B} asks to find the fastest growing function $f(x)$ so that for large $x$ and any given finite sequence $ε_i\in \{0,1\}, i\le f(x)$, there exists $n<x$ such that the congruences $e_{p_i}(n)\equiv ε_i\pmod 2$ hold for all $i\le f(x)$. Here, $p_i$ is the $i$th prime number. In our second result, we are able to show that $f(x)$ can be taken to be at least $c_1 (\log x/(\log\log x)^6)^{1/9}$, with some absolute constant $c_1$, provided that only the first odd prime numbers are involved.

math.NT↗

Netted Binomial Matrices

In this paper we prove that a matrix property of nettedness (all 2x2 cells satisfy a recurrence) is preserved for powers of such a matrix, where the coefficients are all instances of the same sequence. Also, we find an n-dimensional analog of the Q-matrix for the general Pell(Fibonacci) sequence. We close by giving a conjecture about the spectral properties of the binomial matrix we found.

math.CO↗

Spectral Properties of a Binomial Matrix

In this paper we study some further properties of the matrix with entries binom{i-1}{n-j}. We find the generating function for each row and column, and we find the eigenvalues and eigenvectors of this matrix. We also find the spectral properties of this matrix modulo 3 and 5.

math.CO↗

Nonlinearity, Local and Global Avalanche Characteristics of Balanced Boolean Functions

First, we construct a class of functions with good local avalanche characteristics, but bad global avalanche characteristics. We also derive some bounds for the nonlinearity of such functions. It improves upon the results of Son et al., and Sung et al. In our second result we construct a class of highly nonlinear balanced functions with good local and global avalanche characteristics.

math.CO↗

Fast Evaluation, Weights and Nonlinearity of Rotation-Symmetric Functions

We study the nonlinearity and the weight of the rotation-symmetric (RotS) functions defined by Pieprzyk and Qu. We give exact results for the nonlinearity and weight of 2-degree RotS functions with the help of the semi-bent functions and we give the generating function for the weight of the 3-degree RotS function. Based on the numerical examples and our observations we state a conjecture on the nonlinearity and weight of the 3-degree RotS functions.

math.CO↗

Matrix Powers of Column-Justified Pascal Triangles and Fibonacci Sequences

If L, respectively R are matrices with entries binom{i-1,j-1}, respectively binom{i-1,n-j}, it is known that L^2 = I (mod 2), respectively R^3 = I (mod 2), where I is the identity matrix of dimension n > 1 (see P10735-May 1999 issue of the American Mathematical Monthly). We generalize it for any prime p, and give a beautiful connection to Fibonacci numbers.

math.CO↗

p^q-Catalan Numbers and Squarefree Binomial Coefficients

In this paper we consider the generalized Catalan numbers F(s,n)= 1/((s-1)n+1) binom{sn}{n}. We find all $n$ such that for $p$ prime, p^q divides F(p^q,n), q>=1. As a byproduct we settle a question of Hough and the late Simion on the divisibility of the 4-Catalan numbers. We also prove that \binom{p^qn+1}{n}, p^q<=99999, is squarefree for n sufficiently large (explicit), and with the help of the generalized Catalan numbers we find the set of possible exceptions. As consequences, we obtain that binom{4n+1}{n}, binom{9n+1}{n} are squarefree for n> 2^{1518}, respectively n>3^{956}, with at most 2^{18.2}, respectively 3^{15.3} possible exceptions.

math.NT↗

Generating Functions, Weighted and Non-Weighted Sums for Powers of Second-Order Recurrence Sequences

In this paper we find closed form for the generating function of powers of any non-degenerate second-order recurrence sequence, completing a study begun by Carlitz and Riordan in 1962. Moreover, we generalize a theorem of Horadam on partial sums involving such sequences. Also, we find closed forms for weighted (by binomial coefficients) partial sums of powers of any non-degenerate second-order recurrence sequences. As corollaries we give some known and seemingly unknown identities and derive some very interesting congruence relations involving Fibonacci and Lucas sequences.

math.CO↗