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A049336
Table read by rows: T(n,k) = number of 2-connected planar graphs with n >= 1 nodes and 0 <= k <= 3n-6 edges.
6
0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 2, 3, 2, 1, 0, 0, 0, 0, 0, 0, 1, 3, 9, 13, 11, 5, 2, 0, 0, 0, 0, 0, 0, 0, 1, 4, 20, 49, 77, 75, 47, 16, 5, 0, 0, 0, 0, 0, 0, 0, 0, 1, 6, 40, 158, 406, 662, 737, 538, 259, 72, 14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 7, 70, 426, 1645, 4176, 7307, 8871, 7541, 4353, 1671, 378, 50
OFFSET
1,21
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.
EXAMPLE
Table begins:
0;
0, 0;
0, 0, 0, 1;
0, 0, 0, 0, 1, 1, 1;
0, 0, 0, 0, 0, 1, 2, 3, 2, 1;
0, 0, 0, 0, 0, 0, 1, 3, 9, 13, 11, 5, 2;
0, 0, 0, 0, 0, 0, 0, 1, 4, 20, 49, 77, 75, 47, 16, 5;
...
CROSSREFS
KEYWORD
nonn,tabf,easy,nice
AUTHOR
EXTENSIONS
More terms, a(86) onwards, from Gilbert Labelle (labelle.gilbert(AT)uqam.ca), Jan 20 2009
STATUS
approved