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A001430
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Number of graphs with n nodes and n-2 edges.
(Formerly M1187 N0458)
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3
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0, 1, 1, 2, 4, 9, 21, 56, 148, 428, 1305, 4191, 14140, 50159, 185987, 720298, 2905512, 12180208, 52951701, 238253067, 1107432714, 5308573473, 26202267612, 132977762151, 692996060768
(list;
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refs;
listen;
history;
text;
internal format)
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OFFSET
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1,4
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REFERENCES
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J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 146.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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EXAMPLE
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There are 4 graphs with 5 nodes and 3 edges.
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MATHEMATICA
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(* first do *) Needs["Combinatorica`"] (* then *) Table[ NumberOfGraphs[n, n-2], {n, 2, 25}] (* Robert G. Wilson v *)
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CROSSREFS
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Cf. A008406, where this is a diagonal.
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KEYWORD
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nonn,nice,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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