|
%I #6 Mar 31 2012 12:36:05
%S 81,129,942,3186,13278,34314,136086,399018,1537038,4607034,16888062,
%T 51777498,185254926,580089834,2037893214,6478793466,22450788942,
%U 72203998026,247694103486,803564559834,2735884703406,8933648141802
%N Number of (n+1)X(n+1) 0..2 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors
%C Diagonal of A186472
%H R. H. Hardin, <a href="/A186463/b186463.txt">Table of n, a(n) for n = 1..23</a>
%e Some solutions for 3X3
%e ..0..0..2....1..0..0....0..0..1....0..2..0....1..1..0....1..2..0....0..0..0
%e ..0..0..2....2..0..0....0..0..1....2..0..2....2..0..1....0..0..2....2..0..0
%e ..0..0..2....0..2..1....0..0..1....0..2..2....0..2..2....0..0..1....0..2..1
%K nonn
%O 1,1
%A _R. H. Hardin_ Feb 22 2011
| 