A006401 Number of unsensed simple planar maps with n edges and without vertices of degree 1.

1, 0, 0, 1, 1, 2, 5, 10, 28, 86, 285, 1055, 4211

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• more

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

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

Crossrefs

Cf. A006385, A006389, A006395, A006400 (sensed), A379436 (rooted).

Extensions

a(11)-a(12) from Sean A. Irvine, Mar 31 2017

a(0)-a(2) prepended by Andrew Howroyd, Jan 16 2025