%I #7 Apr 20 2020 00:07:57
%S 1,1,6,21,146,1246,13767,252509,5755625,177353720,8354131403,
%T 523250794396,44173651472383,5428616779817049,920678621074132173,
%U 212277158481925445968,69198443091508695982216
%N Number of n X n 0..1 arrays with every element unequal to 0, 1, 5 or 8 king-move adjacent elements, with upper left element zero.
%C Diagonal of A304270.
%H R. H. Hardin, <a href="/A304264/b304264.txt">Table of n, a(n) for n = 1..22</a>
%e Some solutions for n=5
%e ..0..0..1..0..0. .0..0..0..1..0. .0..0..0..0..0. .0..0..0..0..0
%e ..0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..1
%e ..0..0..0..0..0. .0..0..0..0..0. .1..0..0..0..0. .0..0..0..0..0
%e ..0..0..0..1..0. .0..0..0..0..1. .0..0..0..0..1. .1..0..0..0..0
%e ..0..0..0..0..0. .0..1..0..0..0. .0..0..0..0..0. .0..0..0..1..0
%Y Cf. A304270.
%K nonn
%O 1,3
%A _R. H. Hardin_, May 09 2018