

A049336


Triangle T(n,k) = number of 2connected planar graphs with n >= 1 nodes and 0<=k<=3n6 edges.


3



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
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OFFSET

1,21


REFERENCES

A. Gagarin, G. Labelle, P. Leroux and T. Walsh, Structure and enumeration of twoconnected graphs with prescribed threeconnected components, Adv. in Appl. Math. 43 (2009), no. 1, 4674.


LINKS

Ruperto Corso, Table of n, a(n) for n = 1..249
A. Gagarin, G. Labelle, P. Leroux, and T. Walsh, Structure and enumeration of twoconnected graphs with prescribed threeconnected components, Adv. in Appl. Math. 43 (2009), no. 1, pp. 4674.


EXAMPLE

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...


CROSSREFS

Cf. A021103, A003094, A049334.
Sequence in context: A152954 A079175 A202815 * A017888 A017878 A301572
Adjacent sequences: A049333 A049334 A049335 * A049337 A049338 A049339


KEYWORD

nonn,tabf,easy,nice


AUTHOR

Brendan McKay


EXTENSIONS

More terms, a(86) onwards, from Gilbert Labelle (labelle.gilbert(AT)uqam.ca), Jan 20 2009


STATUS

approved



