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Search: id:A054557
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| A054557 |
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Number of labeled pure 2-complexes on n nodes (0-simplexes) with 5 2-simplexes and 10 1-simplexes. |
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8
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| 72, 4824, 32256, 127008, 378000, 940464, 2062368, 4115232, 7629336, 13333320, 22198176, 35485632, 54800928, 82149984, 120000960, 171350208, 239792616, 329596344, 445781952, 594205920, 781648560, 1015906320, 1305888480
(list; graph; listen)
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OFFSET
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5,1
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COMMENT
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Number of {T_1,T_2,...,T_k} where T_i,i=1..k are 3-subsets of an n-set such that {D | D is 2-subset of T_i for some i=1..k} has l elements; k=5,l=10.
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REFERENCES
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V. Jovovic, On the number of two-dimensional simplicial complexes (in Russian), Metody i sistemy tekhnicheskoy diagnostiki, Vypusk 16, Mezhvuzovskiy zbornik nauchnykh trudov, Izdatelstvo Saratovskogo universiteta, 1991.
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FORMULA
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a(n)=72*C(n, 5)+4392*C(n, 6)=n*(n-1)*(n-2)*(n-3)*(n-4)*(61*n-299)/10.
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CROSSREFS
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Sequence in context: A111598 A116312 A111782 this_sequence A103861 A119750 A093272
Adjacent sequences: A054554 A054555 A054556 this_sequence A054558 A054559 A054560
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KEYWORD
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nonn
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AUTHOR
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Vladeta Jovovic (vladeta(AT)Eunet.yu), Apr 10 2000
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), Apr 11 2000
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