A006391 Number of unsensed loopless planar maps with n edges.

1, 1, 2, 5, 14, 45, 191, 871, 4682, 27336, 172706, 1150322, 7989004

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

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, A000260 (rooted), A006390 (sensed).

Extensions

a(8)-a(12) from Sean A. Irvine, Mar 29 2017

a(0)=1 prepended by Andrew Howroyd, Jan 14 2025