A380618 Number of sensed combinatorial maps with n edges and 2 vertices.

1, 2, 8, 38, 275, 2614, 30346, 415360, 6513999, 115063118, 2259975228, 48860184539, 1153140907207, 29502289676802, 813371784160602, 24040797257734161, 758379326971459945, 25432414455826532993, 903508909333199982128, 33897272145242834426910, 1339265974992611047296679

Offset

1,2

Comments

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

Links

Andrew Howroyd, Table of n, a(n) for n = 1..200

Prog

(PARI) \\ Needs G(), InvEulerMTS from A380615.
seq(n, k=2)={my(y='y); Vec(polcoef(InvEulerMTS(G(n, y*(1 + O(y^k)))), k, y))}

Crossrefs

Column 2 of A380615.

Cf. A380237 (planar), A380619 (3 vertices), A380620 (unsensed).

Sequence in context: A265906 A060389 A318917 * A203122 A207157 A198049

Adjacent sequences: A380615 A380616 A380617 * A380619 A380620 A380621

Keyword

nonn

Author

Andrew Howroyd, Jan 28 2025

Status

approved