A006674 Triangulations of a square with no separating triangles (previously "Bordered triangulations of sphere with n nodes"). (Formerly M1631)

1, 1, 2, 6, 18, 68, 282, 1309, 6437, 33264, 177260, 968349

Offset

5,3

References

H. Heesch, Ein zum Vierfarbensatz aquivalenter Satz der Panisochromie [ A theorem of panisochromaticity equivalent to the four color theorem ], pp. 229-253 of Graph Theory in Memory of G. A. Dirac (Sandbjerg, 1985). Edited by L. D. Andersen et al., Annals of Discrete Mathematics, 41. North-Holland Publishing Co., Amsterdam-New York, 1989.

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=5..16.

Crossrefs

Sequence in context: A150079 A150080 A150081 * A006389 A030269 A150082

Adjacent sequences: A006671 A006672 A006673 * A006675 A006676 A006677

Keyword

nonn

Author

N. J. A. Sloane

Extensions

Terms a(13)-a(16) computed with plantri from Gordon Royle, Jun 10 2021

Status

approved