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
KEYWORD
nonn,easy
AUTHOR
Peter J. Cameron, Sep 14 2005
STATUS
approved