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A000103 Number of n-node triangulations of sphere in which every node has gdegree >= 4.
(Formerly M1423 N0559)
+0
2
0, 0, 1, 1, 2, 5, 12, 34, 130, 525, 2472, 12400, 65619, 357504, 1992985, 11284042, 64719885, 375126827, 2194439398, 12941995397, 76890024027, 459873914230, 2767364341936, 16747182732792 (list; graph; listen)
OFFSET

4,5

REFERENCES

R. Bowen and S. Fisk, Generation of triangulations of the sphere, Math. Comp., 21 (1967), 250-252.

D. A. Holton and B. D. McKay, The smallest non-hamiltonian 3-connected cubic planar graphs have 38 vertices, J. Combinat. Theory, B 45 (1988), 305-319.

LINKS

Gunnar Brinkmann and Brendan McKay, plantri and fullgen programs for generation of certain types of planar graph.

Thom Sulanke, Generating triangulations of surfaces (surftri), (also subpages).

EXAMPLE

a(4)=0, a(5)=0 because the tetrahedron and the 5-bipyramid both have vertices of degree 3. a(6)=1 because of the A000109(6)=2 triangulations with 6 nodes (abcdef) the one corresponding to the octahedron (bcde,afec,abfd,acfe,adfb,bedc) has no node of degree 3, whereas the other triangulation (bcdef,afec,abed,ace,adcbf,aeb) has 2 such nodes.

CROSSREFS

Cf. all triangulations: A000109, triangulations with minimum degree 5: A081621.

Sequence in context: A032292 A121956 A131467 this_sequence A101292 A131267 A075202

Adjacent sequences: A000100 A000101 A000102 this_sequence A000104 A000105 A000106

KEYWORD

nonn,hard

AUTHOR

njas

EXTENSIONS

More terms from Hugo Pfoertner (hugo(AT)pfoertner.org), Mar 24 2003

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm) from the Surftri web site, May 05 2007

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Last modified July 24 12:00 EDT 2008. Contains 142294 sequences.


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