[seqfan] Re: A064513, A058201, and the graph degree/diameter problem.

[Allan Wechsler]

I apologize for getting the values backwards. It is as Chris Thompson says:
the old sequence says 25 and is wrong, and the new one says 24, and is
right, agreeing with all online sources I have consulted.

But a(2) still ought to be 5, not 4.

On Tue, Nov 17, 2015 at 9:37 AM, Chris Thompson <cet1 at cam.ac.uk> wrote:

> On Nov 17 2015, Allan Wechsler wrote:
>
> [... snipped...]
>
>> Wikipedia has articles on the degree/diameter problem. The first column of
>> their table (
>>
>
> https://en.wikipedia.org/wiki/Table_of_the_largest_known_graphs_of_a_given_diameter_and_maximal_degree
>
>> ) gives values 2, 5, 10, 15, 25, 32, 50. So their a(5) agrees with the
>> later
>> sequence on OEIS, but their a(2) (and *my* a(2), for that matter!)
>> disagrees with *both* versions on OEIS.
>>
>
> I read the Wikipedia page as saying that a(5) = 24 - admittedly the dark
> blue background could easily lead to misreading!
>
> In any case, that agrees with the EJC Dynamic Survey (updated 2013). The
> Wikipedia link to that seems to be broken: a working one is
>
> http://www.combinatorics.org/ojs/index.php/eljc/article/view/DS14
>
> This also confirms a(6) = 32 as optimal.
>
> --
> Chris Thompson
> Email: cet1 at cam.ac.uk
>
> _______________________________________________
>
> Seqfan Mailing list - http://list.seqfan.eu/
>