[Graphs with n edges]

Christian G. Bower bowerc at usa.net
Thu Oct 10 02:33:03 CEST 2002

I wrote:
> By the way, the offset on A002905 should be 0, not 1.

ID Number: A002905 (Formerly M2486 and N0985)
Sequence:  1,1,1,3,5,12,30,79,227,710,2322,8071,29503,112822,450141,
Name:      Connected graphs with n edges.

Now that I think about it, there are 2 connected graphs with zero edges:
the empty graph and the one node graph. Thus a(0) should be 2.

However, that would change the sequence's location in the database; since
it's a book sequence, we might not want to do that. Another solution is
to change the title to "Nonempty connected graphs with n edges."

This applies to A046091 (except for the part about being a book sequence.)


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