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Search: id:A000103
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| A000103 |
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Number of n-node triangulations of sphere in which every node has gdegree >= 4.
(Formerly M1423 N0559)
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+0
2
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| 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)
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OFFSET
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4,5
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REFERENCES
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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.
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LINKS
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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).
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EXAMPLE
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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.
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CROSSREFS
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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
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KEYWORD
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nonn,hard
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AUTHOR
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njas
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EXTENSIONS
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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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