# [Nauty-list] Directed graphs with loops

Алексей Болгов bolgov.ak at gmail.com
Sun Sep 12 16:50:55 EST 2010

```I need digrahps from 1 to 4 vertices (at least).

2010/9/12 Brendan McKay <bdm at cs.anu.edu.au>

> I believe the number of digraphs with loops is given by OEIS A000595
> (this is without any vertex fixed).  Starting at 1 vertex, it is
> 2, 10, 104, 3044, 291968, 96928992, 112282908928, 458297100061728,
> see  http://www.research.att.com/~njas/sequences/A000595<http://www.research.att.com/%7Enjas/sequences/A000595>and also
> http://www.research.att.com/~njas/sequences/A046858<http://www.research.att.com/%7Enjas/sequences/A046858>.
>
> Currently there is no way to make these digraphs directly using the
> distributed software. Obviously there should be, and I have added it
> to my todo list. Meanwhile there might be some programming hack that
> is not too difficult; what size of digraph are you interested in?
>
> Brendan.
>
> * ??????? ?????? <bolgov.ak at gmail.com> [100912 05:08]:
> > Hi. Maybe my question is silly, but: I've read the manual and tried to
> > generate directed graphs. I used `geng` and `directg` with "-f1". The
> > maximum number of directed graphs I could get - 28 (for n=3). But no one
> of
> > them had self-loops. I need all non-isomorphic directed graphs (w/ and
> w/o
> > loops). So, can I generate directed graphs with loops using standart
> > resources of gtools? And is there any information about the quantity of
> > directed graphs with loops (n=3 for example). Sorry for my bad language.
>
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>
>

--
С уважением, Алексей.
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