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摘要: Prove that if $p$ and $q$ are twin primes greater than 3,then $p+q$ isdivisible by 12.Proof:According to Elementary Methods in Number Theory Exercise ... 阅读全文
posted @ 2012-11-29 23:46 叶卢庆 阅读(182) 评论(0) 推荐(0)
摘要: Prove that if $p$ and $q$ are twin primes greater than 3,then $p+q$ isdivisible by 12.Proof:According to Elementary Methods in Number Theory Exercise ... 阅读全文
posted @ 2012-11-29 23:46 叶卢庆 阅读(109) 评论(0) 推荐(0)
摘要: The prime numbers $p$ and $q$ are called twin primes if$|p-q|=2$.Let $p$ and $q$ be primes.Prove that $pq+1$ is a square ifand only if $p$ and $q$ are... 阅读全文
posted @ 2012-11-29 19:45 叶卢庆 阅读(148) 评论(0) 推荐(0)
摘要: The prime numbers $p$ and $q$ are called twin primes if$|p-q|=2$.Let $p$ and $q$ be primes.Prove that $pq+1$ is a square ifand only if $p$ and $q$ are... 阅读全文
posted @ 2012-11-29 19:45 叶卢庆 阅读(141) 评论(0) 推荐(0)
摘要: Find all primes $p$ such that $29p+1$ is a square.Proof:\begin{equation} 29p+1=t^2\end{equation}So\begin{equation} 29p=(t+1)(t-1)\end{equation}Both ... 阅读全文
posted @ 2012-11-29 17:36 叶卢庆 阅读(132) 评论(0) 推荐(0)
摘要: Find all primes $p$ such that $29p+1$ is a square.Proof:\begin{equation} 29p+1=t^2\end{equation}So\begin{equation} 29p=(t+1)(t-1)\end{equation}Both ... 阅读全文
posted @ 2012-11-29 17:36 叶卢庆 阅读(112) 评论(0) 推荐(0)
摘要: Prove that $n^5-n$ is divisible by 30 for every integer $n$.Proof:\begin{equation} n^5-n=(n-1)n(n+1)(n^2+1)\end{equation}\begin{equation} 6|(n-1)n(n... 阅读全文
posted @ 2012-11-29 17:00 叶卢庆 阅读(107) 评论(0) 推荐(0)
摘要: Prove that $n^5-n$ is divisible by 30 for every integer $n$.Proof:\begin{equation} n^5-n=(n-1)n(n+1)(n^2+1)\end{equation}\begin{equation} 6|(n-1)n(n... 阅读全文
posted @ 2012-11-29 17:00 叶卢庆 阅读(128) 评论(0) 推荐(0)
摘要: Let $n\geq 2$,prove that $(n+1)!+k$ is composite for$k=2,\cdots,n+1$.This shows that there exists arbitrarily longintervals of composite numbers.Proof... 阅读全文
posted @ 2012-11-29 16:28 叶卢庆 阅读(141) 评论(0) 推荐(0)
摘要: Let $n\geq 2$,prove that $(n+1)!+k$ is composite for$k=2,\cdots,n+1$.This shows that there exists arbitrarily longintervals of composite numbers.Proof... 阅读全文
posted @ 2012-11-29 16:28 叶卢庆 阅读(114) 评论(0) 推荐(0)
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