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Search: id:A007816
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| A007816 |
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Abstract simplicial 2-complexes on {1,2,3,...,n+3} which triangulate the 2-sphere: C(n+3,2).(4n+1)!/(3n+3)!. |
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| 1, 10, 195, 5712, 223440, 10929600, 641277000, 43859692800, 3424685806080, 300495408595200, 29262949937020800, 3131187613956864000, 365112996737448960000, 46075561988281233408000
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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W. T. Tutte, A census of planar triangulations, Canad. J. Math., 14 (1962), 21-38.
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MAPLE
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f := n->binomial(n+3, 2)*(4*n+1)!/(3*n+3)!;
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CROSSREFS
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Sequence in context: A072387 A134633 A006436 this_sequence A126463 A152561 A097127
Adjacent sequences: A007813 A007814 A007815 this_sequence A007817 A007818 A007819
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KEYWORD
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nonn,easy,nice
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AUTHOR
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reiner(AT)math.umn.edu (Victor Reiner), edelman(AT)math.umn.edu (Paul Edelman)
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