3n+1 conjecture
http://plus.maths.org/content/taxonomy/term/1196
enHailstones revisited
http://plus.maths.org/content/os/latestnews/may-aug10/hailstones/index
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<p>"Mathematics is not yet ready for such problems." This is what the mathematician John Conway reportedly said about the Collatz conjecture, a simple-looking, yet unsolved mathematical mystery. This week Plus hosted two intrepid work experience students, Sabrina Qian and Joe Dickens, who decided to have a go at this fiendish problem nevertheless. And they made some intriguing discoveries. Here is what they came up with.</p>
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<p><i>"Mathematics is not yet ready for such problems." This is what the mathematician <a href="/issue20/features/conway/index.html">John Conway</a> reportedly said about the Collatz conjecture, a simple-looking, yet unsolved mathematical mystery. This week Plus hosted two intrepid work experience students, Sabrina Qian and Joe Dickens, who decided to have a go at this fiendish problem nevertheless. And they made some intriguing discoveries. Here is what they came up with.</i></p><p><a href="http://plus.maths.org/content/os/latestnews/may-aug10/hailstones/index" target="_blank">read more</a></p>http://plus.maths.org/content/os/latestnews/may-aug10/hailstones/index#comments3n+1 conjectureThu, 08 Jul 2010 23:00:00 +0000mf3445246 at http://plus.maths.org/contentMathematical mysteries: Hailstone sequences
http://plus.maths.org/content/mathematical-mysteries-hailstone-sequences
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<p>This problem is easy to describe but it is one of mathematics' unsolved problems.</p>
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<div class="pub_date">January 1997</div> <!-- plusimport --> <br clear="all"></br>
<p>This problem is easy to describe but it is one of mathematics' unsolved problems.</p> <p>Starting with any positive integer n, form a sequence in the following way:</p> <ul> <li>If n is even, divide it by 2 to give n' = n/2.</li> <li>If n is odd, multiply it by 3 and add 1 to give n' = 3n + 1.</li> </ul> <p>Then take n' as the new starting number and repeat the process. For example:</p><p><a href="http://plus.maths.org/content/mathematical-mysteries-hailstone-sequences" target="_blank">read more</a></p>http://plus.maths.org/content/mathematical-mysteries-hailstone-sequences#comments13n+1 conjecturehailstone evaluatorhailstone sequenceMathematical mysteriesWed, 01 Jan 1997 00:00:00 +0000plusadmin4742 at http://plus.maths.org/content