[seqfan] Re: median graphs

[Russell Webb]

Nice sequence.  Can you point me to the code to calculate it (likely in
Mathematica)?

Thanks,
Russ

On Sun, Apr 14, 2019 at 7:27 PM Brendan McKay <Brendan.McKay at anu.edu.au>
wrote:

> Thanks, I submitted a title change for A054927.
>
> Brendan.
>
> On 15/4/19 12:17 pm, israel at math.ubc.ca wrote:
> > Yes, it seems to be a different definition.  Page 2 of the Liskovetz
> > link in A054927 says:
> >
> >  median graphs, i.e. (n,N)-graphs with N=\lceil n(n−1)/4 \rceil edges
> >
> > while I presume A292623 is using the more usual definition of median
> > graphs
> > (as in e.g. Wikipedia).
> >
> > Cheers,
> > Robert
> >
> > On Apr 14 2019, Brendan McKay wrote:
> >
> >> A054927<http://oeis.org/A054927> is 'Number of connected unlabeled
> >> "median" graphs having n nodes such that complement is also connected.'
> >>
> >> A292623<http://oeis.org/A292623> is 'Number of median graphs on n
> >> nodes.'
> >>
> >> Since median graphs are necessarily connected, it seems like A054927
> >> counts a subset of A292623. But the numbers in A054927 for large n
> >> are bigger.
> >>
> >> What's going on?  Two different definitions of "median"?
> >>
> >> Brendan.
> >>
> >>
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> >>
> >>
> >
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