%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