[seqfan] Re: median graphs

[israel at math.ubc.ca]

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.
>
>
>--
>Seqfan Mailing list - http://list.seqfan.eu/
>
>