%I #6 Apr 21 2020 13:01:37
%S 0,2,56,270,1141,4248,14375,45614,138676,409976,1190740,3421202,
%T 9767347,27782656,78849645
%N Number of n X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.
%C Diagonal of A281205.
%e Some solutions for n=4
%e ..0..1..0..1. .0..1..0..1. .0..0..1..1. .0..1..1..0. .0..1..0..1
%e ..0..0..1..0. .1..1..0..0. .1..0..1..0. .0..0..1..0. .0..1..0..0
%e ..1..0..1..0. .0..1..1..0. .1..0..1..0. .1..0..1..1. .0..1..0..1
%e ..1..0..1..1. .0..0..1..0. .1..0..1..0. .0..1..0..0. .0..1..0..0
%Y Cf. A281205.
%K nonn
%O 1,2
%A _R. H. Hardin_, Jan 17 2017