[seqfan] Re: 9 dots puzzle

[Richard Guy]

I believe that there's a paper by Sol Golomb which answers this.  R.

On Fri, 11 Mar 2011, David Wilson wrote:

> For n = 3 through 10, 2n-2 lines suffice, although I cannot say if this is 
> optimal.
>
> http://www.mathpuzzle.com/dots.html
>
> ----- Original Message ----- From: "Dmitry Kamenetsky" 
> <dmitry.kamenetsky at rsise.anu.edu.au>
> To: "Sequence Fanatics Discussion list" <seqfan at list.seqfan.eu>
> Sent: Friday, March 11, 2011 6:00 PM
> Subject: [seqfan] 9 dots puzzle
>
>>  Hello fans,
>>
>>  Consider the 9 dots puzzle:
>>  http://en.wikipedia.org/wiki/Thinking_outside_the_box#Nine_dots_puzzle
>>  You are asked to join 9 dots (on integer coordinates) using 4 straight,
>>  continuous lines (strokes).
>>
>>  I am now wondering: what is the smallest number of strokes required to
>>  join
>>  all the points arranged in a NxN grid? The sequence starts with 1,3,4. How
>>  to compute the rest of it?
>>
>>  Sincerely,
>>  Dmitry Kamenetsky 
>
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