\documentclass[12pt,reqno]{article}

\usepackage[usenames]{color}
\usepackage{amssymb}
\usepackage{graphicx}
\usepackage{amscd}

\usepackage[colorlinks=true,
linkcolor=webgreen,
filecolor=webbrown,
citecolor=webgreen]{hyperref}

\definecolor{webgreen}{rgb}{0,.5,0}
\definecolor{webbrown}{rgb}{.6,0,0}

\usepackage{color}
\usepackage{fullpage}
\usepackage{float}

\usepackage{psfig}
\usepackage{graphics}
\usepackage{amsmath}
\usepackage{amsthm}
\usepackage{amsfonts}
\usepackage{latexsym}
\usepackage{epsf}

\setlength{\textwidth}{6.5in}
\setlength{\oddsidemargin}{.1in}
\setlength{\evensidemargin}{.1in}
\setlength{\topmargin}{-.5in}
\setlength{\textheight}{8.9in}

\newcommand{\seqnum}[1]{\href{http://oeis.org/#1}{\underline{#1}}}

\begin{document}

\begin{center}
\epsfxsize=4in
\leavevmode\epsffile{logo129.eps}
\end{center}

\theoremstyle{plain}
\newtheorem{theorem}{Theorem}
\newtheorem{corollary}[theorem]{Corollary}
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{proposition}[theorem]{Proposition}

\theoremstyle{definition}
\newtheorem{definition}[theorem]{Definition}
\newtheorem{example}[theorem]{Example}
\newtheorem{conjecture}[theorem]{Conjecture}

\theoremstyle{remark}
\newtheorem{remark}[theorem]{Remark}

\begin{center}
\vskip 1cm{\LARGE\bf The 4-Nicol Numbers Having \\
\vskip .1in
 Five Different Prime Divisors }
\vskip 1cm \large {Qiao-Xiao Jin and Min Tang\footnote{Corresponding author.
This work was supported
by the National Natural Science Foundation of China, Grant No.\
10901002 and the SF of the Education Department of Anhui Province,
Grant No.\ KJ2010A126.}}\\
Department of Mathematics \\
Anhui Normal University\\
Wuhu 241000 \\
P. R. China\\
\href{mailto:tangmin@mail.ahnu.edu.cn}{\tt tangmin@mail.ahnu.edu.cn}\\
\end{center}

\vskip .2in

\begin{abstract}
A positive integer $n$ is called a Nicol number if $n\mid
\varphi(n)+\sigma(n)$, and a t-Nicol number if
$\varphi(n)+\sigma(n)=tn$. In this paper, we show that if $n$ is a
4-Nicol number which has five different prime divisors, then $n=2^{\alpha_{1}}\cdot 3\cdot 5^{\alpha_{3}}\cdot p^{\alpha_{4}}\cdot q^{\alpha_{5}}$, or
$n=2^{\alpha_{1}}\cdot 3\cdot 7^{\alpha_{3}}\cdot p^{\alpha_{4}}\cdot q^{\alpha_{5}}$ with $p\leq 29$.
\end{abstract}


\end{document}

                                                                                

