[seqfan] Re: Rings of regular polygons

[Peter Munn]

If you defined it as including all those where neighbouring polygons
shared an edge, that is including 6 triangles around a point etc., I think
the sequence might be A023645, the number of divisors of n less than n/2.
So, I think your a(13) term should be 1.

Peter

> I don't know what happened to the attachment, it seems my anti virus
> program messed it up.
>
> Here is a link to download the file
>
> https://sites.google.com/site/regularpolygonrings/regular-polygon-rings
>
> Regads
> Felix
>
> 2017-03-26 22:21 GMT+02:00 Neil Sloane <njasloane at gmail.com>:
>
>> Felix,
>> "let a(n) count the rings of regular n-gons such that all centers
>> of the n-gons lie on a circle"  This number is infinite!
>> What did you really mean?
>>
>> I could not open those links you mentioned because they wanted to
>> install
>> some software on my machine, which I would not let them do
>> Best regards
>> Neil
>>
>> Neil J. A. Sloane, President, OEIS Foundation.
>> 11 South Adelaide Avenue, Highland Park, NJ 08904, USA.
>> Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway,
>> NJ.
>> Phone: 732 828 6098; home page: http://NeilSloane.com
>> Email: njasloane at gmail.com
>>
>>
>>
>> On Sun, Mar 26, 2017 at 4:01 PM, Felix Fröhlich <felix.froe at gmail.com>
>> wrote:
>> > Dear Sequence fans,
>> >
>> > let a(n) count the number of rings of regular n-gons such that all
>> centers
>> > of the n-gons lie on the same circle. For example, the ring that can
>> be
>> > formed by regular heptagons is probably well known. Other regular
>> polygons
>> > also appear to admit the construction of such rings. I created some
>> > illustrations in a vector graphics program and those illustrations
>> seem
>> to
>> > suggest that the sequence (with offset 5) starts as follows:
>> >
>> > 1, 1, 1, 2, 2, 2, 1, 4, 0, 2
>> >
>> > A PDF containing the illustrations is attached.
>> >
>> > How could those values be proven correct, and would this be worth of
>> > inclusion in the OEIS?
>> >
>> > Best regards
>> > Felix Fröhlich
>> >
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