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A120412
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Number of different graphs with n = number of vertices plus number of edges.
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0
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1, 1, 2, 2, 3, 5, 7, 10, 16, 25, 40, 66, 111
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,3
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COMMENTS
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Given two integers p, q, one can count the number of different graphs having p vertices and q edges by the standard Polya counting technique. Our sequence is then obtained by summing up the terms with p+q=n.
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LINKS
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Table of n, a(n) for n=1..13.
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EXAMPLE
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a(3) = 2 because there is a graph with 3 vertices and no edges and a graph with 2 vertices and one edge.
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CROSSREFS
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Sequence in context: A097333 A001083 A173696 * A022864 A039894 A133225
Adjacent sequences: A120409 A120410 A120411 * A120413 A120414 A120415
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KEYWORD
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nonn
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AUTHOR
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Petr Vojtechovsky (petr(AT)math.du.edu), Jul 05 2006
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STATUS
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approved
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