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%I #6 Sep 16 2020 19:06:58
%S 1,5,9,28,76,177,367,774,1684,3639,7597,15617,32101,66074,135096,
%T 274104,553668,1116275,2245277,4501938,9000074,17953486,35749382,
%U 71056212,140977366,279246077,552333115,1091040731
%N Number of n X n 0..1 arrays with every element unequal to 0, 1 or 3 king-move adjacent elements, with upper left element zero.
%C Diagonal of A303682.
%e Some solutions for n=5
%e ..0..0..1..1..0. .0..1..1..0..0. .0..0..0..0..1. .0..0..0..1..1
%e ..0..1..1..1..1. .1..1..1..1..0. .0..0..0..0..0. .0..0..0..0..1
%e ..1..1..1..1..1. .1..1..1..1..1. .0..0..0..0..0. .0..0..0..0..0
%e ..1..1..1..1..1. .1..1..1..1..1. .0..0..0..0..0. .0..0..0..0..0
%e ..1..1..1..1..0. .0..1..1..1..1. .1..0..0..0..0. .0..0..0..0..0
%Y Cf. A303682.
%K nonn
%O 1,2
%A _R. H. Hardin_, Apr 28 2018