A380620 Number of unsensed combinatorial maps with n edges and 2 vertices.

1, 2, 8, 33, 198, 1571, 16431, 213831, 3288821

Offset

1,2

Comments

By duality, also the number of unsensed combinatorial maps with n edges and 2 faces.

Links

Table of n, a(n) for n=1..9.

Crossrefs

Column 2 of A380616.

Cf. A380239 (planar), A380618 (sensed), A380621 (3 vertices).

Sequence in context: A393727 A393728 A005040 * A191551 A263627 A172448

Adjacent sequences: A380617 A380618 A380619 * A380621 A380622 A380623

Keyword

nonn,more

Author

Andrew Howroyd, Jan 28 2025

Status

approved