A221133 - OEIS

%I #5 Dec 18 2015 18:18:25

%S 0,9,656,643204,4235650596,259039174953636

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

%C Diagonal of A221139

%e Some solutions for n=3

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

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

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

%K nonn

%O 1,2

%A _R. H. Hardin_ Jan 02 2013