[seqfan] Re: Rings of regular polygons

Luca Petrone luca.petrone at libero.it
Mon Mar 27 07:52:15 CEST 2017

The number of configurations for rings of n-gons are the number of integer 
solution in k (number of rings) of the equation (a - 1) (1 + 2/n) + 4/n + 2/k 
== a, with a (number of sides of the n-gon inside the ring) varying from 1 to 


Luca Petrone

>----Messaggio originale----
>Da: "Andrew Weimholt" <andrew.weimholt at gmail.com>
>Data: 26/03/2017 23.59
>A: "Sequence Fanatics Discussion list"<seqfan at list.seqfan.eu>
>Ogg: [seqfan] Re: Rings of regular polygons
>On Sun, Mar 26, 2017 at 2:15 PM, Peter Munn <techsubs at pearceneptune.co.uk>
>> 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 agree. 26 13-gons DO form a ring.
>Something is wrong with the 13-gons in the his PDF (uneven edge lengths
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