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A006647 Number of graphs with n nodes, n-2 edges and no isolated vertices.
(Formerly M2586)
1
1, 1, 3, 6, 15, 33, 83, 202, 527, 1377, 3744, 10335, 29297, 84396, 248034, 740289, 2245094, 6904206, 21522973, 67936799, 217026480, 701159919, 2289925258, 7556363054, 25184139149, 84743377436, 287815771822, 986345040471, 3409869008578 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,3

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=4..32.

W. L. Kocay, Some new methods in reconstruction theory, pp. 89 - 114 of Combinatorial Mathematics IX. Proc. Ninth Australian Conference (Brisbane, August 1981). Ed. E. J. Billington, S. Oates-Williams and A. P. Street. Lecture Notes Math., 952. Springer-Verlag, 1982.

FORMULA

a(n) = A001430(n) - A001433(n - 1). - Sean A. Irvine, Jun 05 2017

CROSSREFS

Cf. A001430, A001433.

Sequence in context: A105476 A000599 A063832 * A032126 A190525 A032176

Adjacent sequences:  A006644 A006645 A006646 * A006648 A006649 A006650

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Vladeta Jovovic, Mar 02 2008

More terms from Sean A. Irvine, Jun 05 2017

STATUS

approved

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Last modified December 7 22:29 EST 2019. Contains 329850 sequences. (Running on oeis4.)