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Search: id:A125679
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| A125679 |
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Number of combinatorial 2-manifolds with n vertices. |
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+0
1
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OFFSET
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7,1
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LINKS
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Basudeb Datta, Minimal Triangulations of Manifolds, 25 Jan 2007, arXiv:math/0701735
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EXAMPLE
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a(7) = 9 because there are exactly nine 7-vertex combinatorial 2-manifolds, five of which triangulate the 2-sphere S^2, three of which triangulate RP^2 and one triangulates S^1 X S^1.
a(8) = 44 because there are exactly fortyfour 8-vertex combinatorial 2-manifolds, one of which consists of two copies of S(_4)^2, fourteen of which triangulate the 2-sphere S^2, sixteen of which triangulate RP^2, seven triangulate S^1 X S^1 and six triangulate the Klein bottle.
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CROSSREFS
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Sequence in context: A099867 A104470 A084016 this_sequence A037207 A096688 A124983
Adjacent sequences: A125676 A125677 A125678 this_sequence A125680 A125681 A125682
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KEYWORD
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hard,nonn
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AUTHOR
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Jonathan Vos Post (jvospost3(AT)gmail.com), Jan 30 2007
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EXTENSIONS
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Replaced arXiv URL by non-cached version - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 30 2009
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