can anybody extend this new sequence?

[Jeremy Gardiner]

My knowledge of graph theory is limited,
but I think 2 edges between a pair of nodes is sometimes called a skein,
while a loop is a node joined to itself.

Jeremy

From: Max <relf at unn.ac.ru>
Date: Mon, 29 Aug 2005 11:22:52 -0700
To: Jeremy Gardiner <jeremy.gardiner at btinternet.com>
Cc: sequence fans <seqfan at ext.jussieu.fr>
Subject: Re: can anybody extend this new sequence?

Jeremy Gardiner wrote:

> %I A000001
> %S A000001 0,7,640,170555,
> %N A000001 a(n) = number of labeled 3-regular (trivalent) multi-graphs
> without loops on 2n vertices with a maximum of 2 edges between any pair of
> nodes.

2 edges between a pair of nodes form a loop, don't they?
Do you mean that there are no longer loops?

Max


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