[seqfan] Re: Maximal number of touching points between unit spheres

M. F. Hasler seqfan at hasler.fr
Wed Feb 28 06:07:56 CET 2018


Felix,
For n=10 you get at least a(n-1)+4 >= 25,
see figure 1 in the Bezdek & Khan preprint cited in A214813.
- Maximilian




On Tue, Feb 27, 2018 at 11:55 AM, Felix Fröhlich <felix.froe at gmail.com>
wrote:

> Dear SeqFans,
>
> I had the idea for the following sequence:
>
> Maximal total number of touching points between n unit spheres.
>
> With offset 2, I get the following terms:
>
> 1, 3, 6, 9, 12, 15, 18, 21, 24
>
> 1) Can someone with more knowledge of the subject confirm these terms?
> 2) Can someone confirm that this is different from A214813?
> 3) Can someone confirm that this is the same as A008486?
>
> Regarding 2), see second comment in A214813. Regarding 3), there is a
> comment by Sergey Pavlov from Feb 03 2017 in A008486 that may be related to
> this, but I am not sure about it.
>
> So, is this already in the OEIS?
>
> Best regards
> Felix


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