[seqfan] Re: 9 dots puzzle

[Solomon Golomb]

Richard,
I co-authored a paper with John Selfridge titled "Unicursal Polygonal Paths and Other Graphs on Point Lattices," which appeared in the Pi Mu Epsilon Journal, Fall, 1970.
Sol Golomb
PS. Do you know what has become of Selfridge?  Last I heard, several years ago, he was ill. 
S.
On Mar 12, 2011, at 10:26 AM, Richard Guy wrote:

> Sol,
>    Am I wrong in ascribing a solution of the generalized
> ``draw 4 continuous segments through 9 points'' problem
> to you?  Or was it John Selfridge?  Or a collaboration?
> 
>    Best wishes,  R.
> 
> On Sun, 13 Mar 2011, Dmitry Kamenetsky wrote:
> 
>> Great news. Do you know which paper it is, because he has many.
>> 
>> Dmitry
>> 
>> ----------------original message-----------------
>> From: "Richard Guy" rkg at cpsc.ucalgary.ca
>> To: "Sequence Fanatics Discussion list" seqfan at list.seqfan.eu
>> Date: Fri, 11 Mar 2011 17:13:42 -0700 (MST)
>> -------------------------------------------------
>> 
>> 
>>> 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
>