%I #9 Mar 09 2015 04:30:14
%S 1,2,11,195,8969,1232795,471487297,516844071813,1603508113421239,
%T 14148460147460008963,354360105981877906958557,
%U 25210728065407321182797745205,5093486498660018140333056634922039
%N Number of n X n binary matrices containing no more than two 1's in any 2 X 2 sub-block.
%C No more than 1 1 in any 2 X 2 sub-block gives A063443.
%C No more than 3 1's in any 2 X 2 sub-block gives A139810.
%H R. H. Hardin, May 25 2008, <a href="/A140314/b140314.txt">Table of n, a(n) for n = 0..15</a>
%Y Cf. A063443, A139810.
%K nonn
%O 0,2
%A _R. H. Hardin_, May 25 2008