The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #6 Dec 18 2015 18:17:48
%S 1,2,6,18,48,211,1685,17107,194842,2735810,54757712,1541398741,
%T 56647655849,2661035439470
%N Number of n X n 0..4 arrays with each element equal to the number of its horizontal and vertical neighbors equal to 2
%C Every 0 is next to 0 2's, every 1 is next to 1 2's, every 2 is next to 2 2's, every 3 is next to 3 2's, every 4 is next to 4 2's
%C Diagonal of A197061
%e Some solutions for n=4
%e ..2..2..2..1....2..2..1..0....1..2..2..1....0..1..1..1....0..0..0..0
%e ..2..3..2..1....2..2..1..0....1..2..2..1....1..2..2..2....1..1..0..0
%e ..2..3..2..1....1..1..0..0....0..1..1..0....1..2..4..2....2..2..1..0
%e ..2..2..2..1....0..0..0..0....0..0..0..0....1..2..2..2....2..2..1..0
%K nonn
%O 1,2
%A _R. H. Hardin_ Oct 09 2011