A006396 Number of sensed planar maps with n edges and without faces or vertices of degree 1.

1, 0, 1, 2, 4, 10, 36, 132, 616, 3060, 16207, 88990, 503816

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• more

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. A006384, A006388, A006397 (unsensed), A379435 (rooted).

Extensions

a(9)-a(12) from Sean A. Irvine, Mar 28 2017

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