|
%I #5 Mar 31 2012 12:36:19
%S 39,235,1473,12123,126631,1757318,32090135,788075131,25821271397,
%T 1137500732205,67142445815228,5324910690451856,566582175357963128,
%U 80968803488105203945,15531562746293796709197,4000671284977284767088973
%N Number of (n+2)X(n+2) symmetric binary matrices without the pattern 0 1 1 diagonally, vertically, antidiagonally or horizontally
%H R. H. Hardin, <a href="/A190538/b190538.txt">Table of n, a(n) for n = 1..20</a>
%e Some solutions for 4X4
%e ..1..0..1..0....1..0..0..1....0..0..0..1....1..1..1..1....0..0..1..0
%e ..0..0..0..0....0..0..0..1....0..0..0..0....1..0..0..1....0..0..0..1
%e ..1..0..0..0....0..0..1..0....0..0..0..0....1..0..0..0....1..0..0..0
%e ..0..0..0..0....1..1..0..0....1..0..0..0....1..1..0..1....0..1..0..1
%K nonn
%O 1,1
%A _R. H. Hardin_ May 12 2011
| 