A141485 - OEIS

A141485

Number of n X n binary matrices, symmetric about both diagonal and antidiagonal, with no more than 1 one in any 2 X 2 subblock.

%I #7 Mar 09 2015 04:33:11

%S 1,2,1,5,4,21,21,158,225,2181,4032,53517,135895,2389270,8052775,

%T 191382781,871834816,27710789575,168906089337,7222686132766,

%U 59221019073815,3396328221185505,37352381844672086,2877824684844515547

%N Number of n X n binary matrices, symmetric about both diagonal and antidiagonal, with no more than 1 one in any 2 X 2 subblock.

%H R. H. Hardin, Aug 09 2008, <a href="/A141485/b141485.txt">Table of n, a(n) for n = 0..30</a>

%K nonn

%O 0,2

%A _R. H. Hardin_, Aug 09 2008