Quandaries and Queries


I am a student who want to know:
Is there any formula for counting the number of trees (graphs)?

Hi Ali,

If you mean the number of spanning trees of a graph on n labelled points it is due to Cayley and is nn-2.


Thank you for your answering to my question about trees, but I mean the number of unlabelled trees?

Best regards,

Hi again Ali,

Go to http://www.research.att.com/~njas/sequences/index.html and enter the sequence

1, 2, 3, 6, 11, 23, 47, 106, 235


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