A049336 Table read by rows: T(n,k) = number of 2-connected planar graphs with n >= 1 nodes and 0 <= k <= 3n-6 edges.

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

Author

Brendan McKay

Keywords

• nonn
• tabf
• easy
• nice

Examples

			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;
  ...
		

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 two-connected graphs with prescribed three-connected components, Adv. in Appl. Math. 43 (2009), no. 1, pp. 46-74.

Crossrefs

Cf. A021103, A003094, A049334.

Extensions

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