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Number of n X n 0..1 arrays with every element unequal to 0, 1, 2 or 3 king-move adjacent elements, with upper left element zero.
0

%I #6 Sep 16 2020 19:07:38

%S 1,8,23,84,219,569,1476,3614,8730,20886,49351,114833,265877,610405,

%T 1396025,3172297,7195606,16230944,36563883,82008735,183813328,

%U 410490052

%N Number of n X n 0..1 arrays with every element unequal to 0, 1, 2 or 3 king-move adjacent elements, with upper left element zero.

%C Diagonal of A303727.

%e Some solutions for n=5

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

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

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

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

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

%Y Cf. A303727.

%K nonn

%O 1,2

%A _R. H. Hardin_, Apr 29 2018