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A021103

Number of two-connected (or biconnected) planar graphs with n nodes.

0, 0, 0, 1, 3, 9, 44, 294, 2893, 36496, 545808, 9029737, 159563559, 2952794985, 56589742050

OFFSET

0,5

COMMENTS

For n < 3, conventions vary: Read & Wilson set a(2) = 0, but Gagarin et al. set a(2) = 1. - Andrey Zabolotskiy, Jun 07 2023

REFERENCES

R. C. Read and R. J. Wilson, An Atlas of Graphs, Oxford, 1998. See p. 229.

LINKS

A. Gagarin, G. Labelle, P. Leroux, and T. Walsh, Structure and enumeration of two-connected graphs with prescribed three-connected components, Adv. in Appl. Math. 43 (2009), no. 1, pp. 46-74. See (116) on p. 69.

CROSSREFS

Row sums of A049336.

The labeled version is A096331.

KEYWORD

nonn,more

AUTHOR

EXTENSIONS

a(12)-a(14) from Gilbert Labelle (labelle.gilbert(AT)uqam.ca), Jan 20 2009

Offset 0 from Michel Marcus, Jun 05 2023

a(2) changed back to 0 by Georg Grasegger and Andrey Zabolotskiy, Jun 07 2023

STATUS

approved

URL: https://oeis.org/A021103