A378074 Number of embeddings on the sphere of 2-connected homeomorphically irreducible planar graphs with n nodes.

0, 0, 0, 1, 2, 9, 47, 420, 4673, 63253, 927238, 14342093, 229607392, 3776227106, 63482545872, 1087322656758, 18927037827561

Offset: 1

Author

Andrew Howroyd, Nov 15 2024

Keywords

• nonn
• more

Comments

Homeomorphically irreducible means each vertex has a degree of at least 3.

Crossrefs

Row sums of A378075.

Cf. A000944, A034889, A187927, A378076.

Formula

a(n) = A000944(n) + A187927(n).