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%I #10 Aug 04 2018 10:35:10
%S 0,9,10,196,720,6400,34272,242064,1460368,9610000,60194160,387459856,
%T 2455717680,15698085264,99863349040,636989149456,4056917039280,
%U 25859869267600,164758872493872,1049992515273744,6690497356781488
%N Number of 2 X n arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, with no occupancy greater than 2.
%C Row 2 of A221200.
%H R. H. Hardin, <a href="/A221201/b221201.txt">Table of n, a(n) for n = 1..86</a>
%F Empirical: a(n) = 7*a(n-1) + 14*a(n-2) - 126*a(n-3) + 504*a(n-5) - 224*a(n-6) - 448*a(n-7) + 256*a(n-8).
%F Empirical g.f.: x^2*(9 - 53*x + 342*x^3 - 124*x^4 - 448*x^5 + 256*x^6) / ((1 - 2*x)*(1 + 2*x)*(1 - 7*x + 4*x^2)*(1 - 14*x^2 + 16*x^4)). - _Colin Barker_, Aug 04 2018
%e Some solutions for n=3:
%e ..1..2..1....0..2..0....0..2..1....0..2..0....0..2..2....2..2..0....1..2..0
%e ..0..2..0....0..2..2....0..2..1....1..2..1....0..2..0....0..2..0....1..2..0
%Y Cf. A221200.
%K nonn
%O 1,2
%A _R. H. Hardin_, Jan 04 2013
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