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Number of n X n 0..2 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor.
0

%I #9 Jul 19 2023 09:40:47

%S 1,35,5493,6092872,56006562037,4095290003129296,

%T 2365289879500027706428,10827985400073310953152590562,

%U 392915439811314078675718437985175633,112991429416970014192131075985467073204579858

%N Number of n X n 0..2 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor.

%e Some solutions for n=3

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

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

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

%Y Diagonal of A202889.

%K nonn,more

%O 1,2

%A _R. H. Hardin_, Dec 25 2011