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A093351
Number of labeled n-vertex graphs with a 2-component.
3
0, 0, 1, 3, 9, 65, 885, 20769, 904799, 75119535, 12059144775, 3777502008115, 2321770382163177, 2810098818045932049, 6714509196242295683053, 31734155232117923771498025, 297105206555826680431032956415
OFFSET
0,4
FORMULA
E.g.f.: (1-exp(-x^2/2))*Sum(2^binomial(n, 2)*x^n/n!, n=0..infinity).
CROSSREFS
Cf. A093352.
Sequence in context: A228776 A087673 A046239 * A018543 A026090 A119751
KEYWORD
nonn
AUTHOR
Goran Kilibarda, Vladeta Jovovic, Apr 26 2004
STATUS
approved