# [seqfan] Re: Discrepancy between definition and terms in A257481?

Neil Sloane njasloane at gmail.com
Mon May 18 21:41:46 CEST 2015

```Felix (I am in London with only limited access to email)

I agree there is something very wrong with A257481.
The original definition was unclear to me, so I made a guess,
which was obviously wrong.

I will replace the definition with a new guess, and
assign the present defintion, which seems to give the values
0,0,0,0,0,0,1,1,2,3,4,5,7 (for n >= 0) to a new sequence  A257954

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.
Email: njasloane at gmail.com

On Mon, May 18, 2015 at 4:27 PM, Brad Klee <bradklee at gmail.com> wrote:

> Hi Felix,
>
> The sequence is cross-referenced with A182619.
>
> "Number of vertices that are connected to two edges in a spiral without
> holes constructed with n hexagons."
>
> It could be that the "chain" is a linear object. For n=12 the chain would
> spiral around to enclose 3 of its "links" with the other 9 circles.
>
> I agree it is confusing, and could maybe use an illustration.
>
> Thanks,
>
>
>
>
> On Mon, May 18, 2015 at 3:20 AM, Felix FrÃ¶hlich <felix.froe at googlemail.com
> >
> wrote:
>
> > Dear SeqFans
> >
> > the definition says "a(n) is the maximal number of circles that can be
> > enclosed by a chain of n circles". So why does the example say "For a(7),
> > one circle can be completely enclosed by six surrounding circles"? Isn't
> > that an example for the value of a(6)? Same goes for the example for
> a(10).
> > Shouldn't a(10), by the definition of the sequence, give the maximum
> number
> > of circles that can be surrounded by a chain of ten circles? Or am I
> simply
> > completely misunderstanding something about the sequence? Can someone
> > clarify how the definition, example and terms of the sequence correlate
> to
> > each other?
> >
> > Best regards
> > Felix FrÃ¶hlich
> >
> > _______________________________________________
> >
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> >
>
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>
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>
```