A006400 Number of sensed simple planar maps with n edges and without vertices of degree 1. (Formerly M1404)

1, 0, 0, 1, 1, 2, 5, 11, 33, 117, 431, 1755, 7485

Offset

0,6

Comments

A simple planar map is a planar map without loops or parallel edges. - Andrew Howroyd, Jan 16 2025

References

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=0..12.

Timothy R. Walsh, Generating nonisomorphic maps without storing them, SIAM J. Algebraic Discrete Methods 4 (1983), no. 2, 161-178.

Crossrefs

Cf. A006384, A006388, A006394, A006401 (unsensed), A379436 (rooted).

Sequence in context: A056365 A276548 A353016 * A254342 A080068 A226919

Adjacent sequences: A006397 A006398 A006399 * A006401 A006402 A006403

Keyword

nonn,more

Author

N. J. A. Sloane

Extensions

a(11) and a(12) from Sean A. Irvine, Mar 30 2017

a(0)-a(2) prepended by Andrew Howroyd, Jan 14 2025

Status

approved