|
%I #6 Apr 21 2020 13:00:19
%S 0,1,68,1022,7803,46610,221212,926077,3549039,12749511,43675963,
%T 144504080,466130380
%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 two elements, and with new values introduced in order 0 sequentially upwards.
%C Diagonal of A281056.
%e Some solutions for n=4
%e ..0..1..0..0. .0..1..1..0. .0..1..1..0. .0..1..1..0. .0..1..0..1
%e ..0..1..1..0. .0..0..1..0. .0..0..1..1. .0..1..1..0. .0..1..0..1
%e ..0..0..0..0. .0..1..1..0. .1..0..1..0. .1..0..1..1. .1..0..1..0
%e ..1..0..1..1. .1..0..1..0. .0..0..1..1. .1..0..0..1. .1..1..1..0
%Y Cf. A281056.
%K nonn
%O 1,3
%A _R. H. Hardin_, Jan 13 2017
| 