A213701 - OEIS

%I #4 Jun 18 2012 07:09:15

%S 5148,168382284,193946752094,34389632236877,2256314178023600,

%T 72037480156866493,1425762604012263360,19265705246048238885,

%U 196522537519121864954,1582723194473524459497,10592676749133340851406

%N Half the number of 6X6 0..n symmetric arrays with no 2X2 subblock summing to 2n

%C Row 5 of A213697

%H R. H. Hardin, <a href="/A213701/b213701.txt">Table of n, a(n) for n = 1..15</a>

%e Some solutions for n=4

%e ..4..4..4..3..4..3....0..3..2..2..1..2....4..2..4..2..2..1....0..3..2..1..3..4

%e ..4..0..1..1..2..3....3..3..4..1..0..4....2..3..1..0..1..0....3..4..4..4..2..1

%e ..4..1..3..4..2..3....2..4..4..1..2..4....4..1..1..0..4..4....2..4..4..1..0..1

%e ..3..1..4..0..1..4....2..1..1..3..3..3....2..0..0..4..3..4....1..4..1..1..0..4

%e ..4..2..2..1..3..3....1..0..2..3..0..4....2..1..4..3..1..1....3..2..0..0..0..3

%e ..3..3..3..4..3..0....2..4..4..3..4..4....1..0..4..4..1..0....4..1..1..4..3..1

%K nonn

%O 1,1

%A _R. H. Hardin_ Jun 18 2012