%I #7 Apr 20 2020 19:38:33
%S 1,1,6,31,247,2905,46165,1143583,41368803,2165406865,168220637918,
%T 19176703676628,3204799103321623,788247777299643666,
%U 284810105663632654341,151134158955831615046217
%N Number of n X n 0..1 arrays with every element unequal to 0, 1, 4 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
%C Diagonal of A318545.
%H R. H. Hardin, <a href="/A318539/b318539.txt">Table of n, a(n) for n = 1..21</a>
%e Some solutions for n=5
%e ..0..0..0..0..0. .0..0..0..1..0. .0..0..0..0..0. .0..0..0..0..0
%e ..0..0..0..0..0. .1..0..0..0..0. .0..0..1..0..0. .0..0..0..1..0
%e ..0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0. .1..0..0..0..0
%e ..0..1..0..0..1. .0..1..0..0..0. .0..0..0..0..0. .0..0..0..0..1
%e ..0..0..0..0..0. .0..0..0..1..0. .0..0..0..1..0. .0..0..0..0..0
%Y Cf. A318545.
%K nonn
%O 1,3
%A _R. H. Hardin_, Aug 28 2018