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A047764
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Number of dissectable polyhedra with n tetrahedral cells and symmetry of type Q.
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12
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0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 12, 0, 0, 0, 0, 0, 30, 0, 0, 0, 0, 0, 55, 0, 0, 0, 0, 0, 143, 0, 0, 0, 0, 0, 273, 0, 0, 0, 0, 0, 728, 0, 0, 0, 0, 0, 1428, 0, 0, 0, 0, 0, 3876, 0, 0, 0, 0, 0, 7752
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OFFSET
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1,20
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COMMENTS
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One of 17 different symmetry types comprising A007173 and A027610 and one of 10 for A371351. Also the number of tetrahedral clusters or polyominoes of the regular tiling with Schläfli symbol {3,3,oo}, both having type Q achiral symmetry and n tetrahedral cells. The center of symmetry is the center of a tetrahedral face (2.10); the order of the symmetry group is 12. An achiral polyomino is identical to its reflection. - Robert A. Russell, Mar 22 2024
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LINKS
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FORMULA
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If n=6m+2 then A047749((n-2)/6), otherwise 0.
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MATHEMATICA
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Table[Switch[Mod[n, 12], 2, 6Binomial[(n-2)/4, (n-2)/12], 8, 12Binomial[(n-4)/4, (n-2)/6], _, 0]/(n+4), {n, 50}] (* Robert A. Russell, Mar 22 2024 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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