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
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.
Extensions
a(9)-a(12) from Sean A. Irvine, Mar 29 2017
a(0)-a(1) prepended by Andrew Howroyd, Jan 16 2025