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A112578 Number of indecomposable 3-D arrays of 0's and 1's with plane sums 2. 2
0, 8, 900, 359424, 370828800, 820150272000, 3435918974208000, 24957654229057536000, 294060698786444083200000, 5334667831784096818790400000, 42889554205720574193041408000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

REFERENCES

P. J. Cameron and T. W. Mueller, Decomposable functors and the exponential principle, II, in preparation

LINKS

Table of n, a(n) for n=1..11.

P. J. Cameron and T. W. Mueller, Decomposable functors and the exponential principle, II, arXiv:0911.3760 [math.CO]

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.

EXAMPLE

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

CROSSREFS

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

Sequence in context: A027725 A265239 A290023 * A112579 A064072 A146536

Adjacent sequences:  A112575 A112576 A112577 * A112579 A112580 A112581

KEYWORD

nonn,easy

AUTHOR

Peter J. Cameron, Sep 14 2005

STATUS

approved

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Last modified January 17 11:57 EST 2022. Contains 350394 sequences. (Running on oeis4.)