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Number of n X n 0..3 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4 and at least one element with value (x(i,j)-1) mod 4, no adjacent elements equal, and upper left element zero
0

%I #5 Dec 18 2015 18:18:45

%S 0,2,50,2080,344136,448752816,1729680196768,24300980960474112,

%T 1325427072324524913988

%N Number of n X n 0..3 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4 and at least one element with value (x(i,j)-1) mod 4, no adjacent elements equal, and upper left element zero

%C Diagonal of A231049

%e Some solutions for n=4

%e ..0..1..0..1....0..3..0..3....0..1..2..1....0..3..0..1....0..1..0..1

%e ..0..3..2..3....2..1..2..1....0..3..0..1....0..1..2..1....0..3..2..1

%e ..2..3..0..1....3..0..3..0....0..3..2..3....2..1..2..1....0..3..0..3

%e ..2..1..2..1....3..2..1..2....2..1..0..1....0..3..0..1....2..1..2..3

%K nonn

%O 1,2

%A _R. H. Hardin_, Nov 03 2013