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 <title>Open Problem Garden - Divisibility of central binomial coefficients - Comments</title>
 <link>http://openproblemgarden.org/op/divisibility_of_central_binomial_coefficients</link>
 <description>Comments for &quot;Divisibility of central binomial coefficients&quot;</description>
 <language>en</language>
<item>
 <title>It seems Problem (1) was  (re: Divisibility of central binomial coefficients)</title>
 <link>http://openproblemgarden.org/op/divisibility_of_central_binomial_coefficients#comment-75594</link>
 <description>&lt;p&gt;It seems Problem (1) was solved last year, see http://arxiv.org/abs/1010.3070&lt;/p&gt;
&lt;p&gt;How about Problem 2? &lt;/p&gt;
</description>
 <pubDate>Sun, 29 Jun 2014 11:06:57 +0200</pubDate>
 <dc:creator>Anonymous</dc:creator>
 <guid isPermaLink="false">comment 75594 at http://openproblemgarden.org</guid>
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 <title>Reference for problem (2)  (re: Divisibility of central binomial coefficients)</title>
 <link>http://openproblemgarden.org/op/divisibility_of_central_binomial_coefficients#comment-7193</link>
 <description>&lt;p&gt;It appears that the right reference for question 2 should be &lt;a href=&quot;http://oeis.org/A151750&quot;&gt;A151750&lt;/a&gt; instead.&lt;/p&gt;
</description>
 <pubDate>Mon, 23 Jul 2012 06:44:51 +0200</pubDate>
 <dc:creator>Ng Yong Hao</dc:creator>
 <guid isPermaLink="false">comment 7193 at http://openproblemgarden.org</guid>
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 <title>2, 10, and 3159 are not valid for problem (2)  (re: Divisibility of central binomial coefficients)</title>
 <link>http://openproblemgarden.org/op/divisibility_of_central_binomial_coefficients#comment-7128</link>
 <description>&lt;p&gt;In the initial comment five values are stated to be not divisible by 3, 5, 7, and 11. That is true for 1 and 3160 but not for 2, 10, and 3159:&lt;/p&gt;
&lt;p&gt;The last base-3-digit of 2 is 2. The last base-11-digit of 10 is 10. The last base-5-digit 3159 is 4. &lt;/p&gt;
&lt;p&gt;Or check these facts:&lt;/p&gt;
&lt;p&gt;&lt;img class=&quot;teximage&quot; src=&quot;/files/tex/6caf0aac9bf6b7b52ae2f687a82c639c5d7dc86f.png&quot; alt=&quot;$ {{2 \times 2} \choose 2} = 6 = 3 \times 2 $&quot; /&gt; &lt;/p&gt;
&lt;p&gt;&lt;img class=&quot;teximage&quot; src=&quot;/files/tex/20ce8fd08f5092af0afaa1730626852f1860801c.png&quot; alt=&quot;$ {{2 \times 10} \choose 10} = 184756 = 11 \times 16796 $&quot; /&gt; &lt;/p&gt;
&lt;p&gt;2 and 3159 are not in the sequence A030979 (mentioned in the bibliography). &lt;/p&gt;
</description>
 <pubDate>Wed, 18 Jan 2012 03:25:37 +0100</pubDate>
 <dc:creator>Anonymous</dc:creator>
 <guid isPermaLink="false">comment 7128 at http://openproblemgarden.org</guid>
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 <title>Does not look like it.
  (re: Divisibility of central binomial coefficients)</title>
 <link>http://openproblemgarden.org/op/divisibility_of_central_binomial_coefficients#comment-6974</link>
 <description>&lt;p&gt;Does not look like it.&lt;/p&gt;
</description>
 <pubDate>Fri, 27 May 2011 17:00:34 +0200</pubDate>
 <dc:creator>Anonymous</dc:creator>
 <guid isPermaLink="false">comment 6974 at http://openproblemgarden.org</guid>
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 <title>Problem 1 solved?  (re: Divisibility of central binomial coefficients)</title>
 <link>http://openproblemgarden.org/op/divisibility_of_central_binomial_coefficients#comment-6921</link>
 <description>&lt;p&gt;Looks like Problem 1 was solved by http://arxiv.org/PS_cache/arxiv/pdf/1010/1010.3070v1.pdf&lt;/p&gt;
</description>
 <pubDate>Mon, 14 Mar 2011 20:51:32 +0100</pubDate>
 <dc:creator>tba</dc:creator>
 <guid isPermaLink="false">comment 6921 at http://openproblemgarden.org</guid>
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<item>
 <title>Divisibility of central binomial coefficients</title>
 <link>http://openproblemgarden.org/op/divisibility_of_central_binomial_coefficients</link>
 <description>&lt;table cellspacing=&quot;10&quot;&gt;
&lt;tr&gt;
  &lt;td&gt;
    Author(s):
        &lt;a href=&quot;/category/graham&quot;&gt;Graham&lt;/a&gt;&amp;nbsp;&amp;nbsp;
  &lt;/td&gt;
  &lt;td align=right&gt;
    Subject:
        &lt;a href=&quot;/category/number_theory_0&quot;&gt;Number Theory&lt;/a&gt; » &lt;a href=&quot;/category/combinatorial_number_theory&quot;&gt;Combinatorial N.T.&lt;/a&gt;&amp;nbsp;&amp;nbsp;
  &lt;/td&gt;
&lt;/tr&gt;

&lt;tr&gt;
  &lt;td colspan=2&gt;
    &lt;table border=1 cellspacing=&quot;5&quot;&gt;
      &lt;tr&gt;&lt;td&gt;
        &lt;div class=&quot;envtheorem&quot;&gt;&lt;b&gt;Problem&amp;nbsp;&amp;nbsp;(1)&lt;/b&gt;&amp;nbsp;&amp;nbsp; Prove that there exist infinitely many positive integers &lt;img class=&quot;teximage&quot; src=&quot;/files/tex/ec63d7020a64c039d5f6703b8fa3ab7393358b5b.png&quot; alt=&quot;$ n $&quot; /&gt; such that &lt;img class=&quot;teximage&quot; src=&quot;/files/tex/9a2e7bf7e3a51324285eef8a82042a439d4c15b6.png&quot; alt=&quot;$$\gcd({2n\choose n}, 3\cdot 5\cdot 7) = 1.$$&quot; /&gt;  &lt;/div&gt;
&lt;div class=&quot;envtheorem&quot;&gt;&lt;b&gt;Problem&amp;nbsp;&amp;nbsp;(2)&lt;/b&gt;&amp;nbsp;&amp;nbsp; Prove that there exists only a finite number of positive integers &lt;img class=&quot;teximage&quot; src=&quot;/files/tex/ec63d7020a64c039d5f6703b8fa3ab7393358b5b.png&quot; alt=&quot;$ n $&quot; /&gt; such that &lt;img class=&quot;teximage&quot; src=&quot;/files/tex/57b37bf3adc8403140096ce71611b82e09ece96f.png&quot; alt=&quot;$$\gcd({2n\choose n}, 3\cdot 5\cdot 7\cdot 11) = 1.$$&quot; /&gt;  &lt;/div&gt;

      &lt;/tr&gt;&lt;/td&gt;
    &lt;/table&gt;
  &lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;</description>
 <category domain="http://openproblemgarden.org/category/graham">Graham, Ronald L.</category>
 <category domain="http://openproblemgarden.org/category/number_theory_0">Number Theory</category>
 <category domain="http://openproblemgarden.org/category/combinatorial_number_theory">Combinatorial Number Theory</category>
 <comments>http://openproblemgarden.org/op/divisibility_of_central_binomial_coefficients#comment</comments>
 <pubDate>Sun, 05 Aug 2007 05:26:20 +0200</pubDate>
 <dc:creator>maxal</dc:creator>
 <guid isPermaLink="false">506 at http://openproblemgarden.org</guid>
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