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Number of (n+2)X(n+2) symmetric binary matrices without the pattern 1 1 1 diagonally, vertically or horizontally
1

%I #7 Mar 31 2012 12:36:19

%S 41,418,7196,204512,10058896,841847949,119691599225,29020894570697,

%T 11983601899221278,8426537547806386479,10092907365256801760968,

%U 20589467353675961113678823,71537585310236891049512559411

%N Number of (n+2)X(n+2) symmetric binary matrices without the pattern 1 1 1 diagonally, vertically or horizontally

%H R. H. Hardin, <a href="/A190421/b190421.txt">Table of n, a(n) for n = 1..14</a>

%e Some solutions for n=2

%e ..1..0..1..0....1..1..0..1....1..0..0..1....0..0..1..1....1..0..1..0

%e ..0..1..0..1....1..0..0..1....0..1..0..1....0..0..0..1....0..1..1..0

%e ..1..0..0..0....0..0..1..0....0..0..0..0....1..0..1..0....1..1..0..0

%e ..0..1..0..0....1..1..0..1....1..1..0..0....1..1..0..0....0..0..0..0

%K nonn

%O 1,1

%A _R. H. Hardin_ May 10 2011