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A112579
Number of 3-D arrays of 0's and 1's with plane sums 2.
2
0, 8, 900, 366336, 378028800, 833156928000, 3477528928742400, 25183876050321408000, 296058177312000019660800, 5362158372805111867637760000, 143458227395428379364635443200000
OFFSET
1,2
REFERENCES
P. J. Cameron and T. W. Mueller, Decomposable functors and the exponential principle, II, in preparation
LINKS
P. J. Cameron and T. W. Mueller, Decomposable functors and the exponential principle, II, arXiv:0911.3760 [math.CO]
FORMULA
a(n) = b(n) + Sum (k/n)*(n choose k)^3*b(k)*a(n-k), where b(n) counts indecomposable arrays (A112578).
EXAMPLE
a(2)=8: six pairs of opposite edges and two inscribed tetrahedra.
CROSSREFS
Cf. A001499 (2-D case), A112578, A112580.
Sequence in context: A375892 A290023 A112578 * A064072 A146536 A189646
KEYWORD
nonn,easy
AUTHOR
Peter J. Cameron, Sep 14 2005
STATUS
approved