A006399 Number of unsensed planar maps with n edges and without loops or isthmuses.

1, 0, 1, 2, 4, 8, 27, 76, 295, 1188, 5462, 26580, 138110

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. A006385, A006391, A006398 (sensed), A099553 (rooted).

Extensions

a(9)-a(12) from Sean A. Irvine, Mar 29 2017

a(0)-a(1) prepended by Andrew Howroyd, Jan 16 2025