A112578 Number of indecomposable 3-D arrays of 0's and 1's with plane sums 2.

0, 8, 900, 359424, 370828800, 820150272000, 3435918974208000, 24957654229057536000, 294060698786444083200000, 5334667831784096818790400000, 42889554205720574193041408000000

Offset: 1

Author

Peter J. Cameron, Sep 14 2005

Keywords

• nonn
• easy

Examples

			a(2)=8: six pairs of opposite edges and two inscribed tetrahedra.
		

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]

Crossrefs

Cf. A010796 (2-D case), A112579, A112580.

Formula

a(1)=0, a(n) = (n!)^2*b(n)/2^n for n>1, where b(0)=1 and sum (n-1 choose k-1)*((2n-2k-1)!!)^2*b(k) = ((2n-1)!!)^2.