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Search: id:A112579
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| A112579 |
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Number of 3-D arrays of 0's and 1's with plane sums 2. |
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+0
3
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| 0, 8, 900, 366336, 378028800, 833156928000, 3477528928742400, 25183876050321408000, 296058177312000019660800, 5362158372805111867637760000, 143458227395428379364635443200000
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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P. J. Cameron and T. W. Mueller, Decomposable functors and the exponential principle, II, in preparation
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FORMULA
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a(n) = b(n) + Sum (k/n)*(n choose k)^3*b(k)*a(n-k), where b(n) counts indecomposable arrays (A112578)
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EXAMPLE
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a(2)=8: six pairs of opposite edges and two inscribed tetrahedra
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CROSSREFS
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Cf. A001499 (2-D case), A112578, A112580.
Sequence in context: A097818 A027725 A112578 this_sequence A064072 A146536 A024111
Adjacent sequences: A112576 A112577 A112578 this_sequence A112580 A112581 A112582
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KEYWORD
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nonn,easy
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AUTHOR
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Peter J. Cameron (p.j.cameron(AT)qmul.ac.uk), Sep 14 2005
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