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Number of 4 X n arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, with no occupancy greater than 2.
1

%I #8 May 05 2021 10:00:07

%S 0,289,212,427716,4984812,1026177156,30374196832,3043294206016,

%T 133567666236732,10038761087929924,525060302368983108,

%U 34891927404610766400,1974298747702764055248,124298442666315631470276

%N Number of 4 X n arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, with no occupancy greater than 2.

%C Row 4 of A221200.

%H R. H. Hardin, <a href="/A221203/b221203.txt">Table of n, a(n) for n = 1..15</a>

%e Some solutions for n=3

%e ..1..2..0....0..2..2....0..2..2....0..2..0....0..2..0....0..2..1....0..2..1

%e ..0..2..0....0..2..1....0..2..0....1..2..1....2..2..1....2..2..0....0..2..1

%e ..0..2..2....0..2..1....0..2..1....2..2..0....0..2..0....0..2..0....1..2..0

%e ..1..2..0....0..2..0....1..2..0....0..2..0....1..2..0....1..2..0....0..2..1

%Y Cf. A221200.

%K nonn

%O 1,2

%A _R. H. Hardin_ Jan 04 2013