A006401 Number of connected planar maps without vertices of degree 1. (Formerly M1384)

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

Offset

3,3

References

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=3..12.

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

Crossrefs

Sequence in context: A257889 A363388 A287963 * A283460 A102964 A075885

Adjacent sequences: A006398 A006399 A006400 * A006402 A006403 A006404

Keyword

nonn,more

Author

N. J. A. Sloane.

Extensions

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

Status

approved