A141511 - OEIS

A141511

Number of n X n binary matrices, symmetric about both diagonal and antidiagonal, with no more than 3 ones in any 2 X 2 subblock.

%I #6 Mar 09 2015 00:18:00

%S 1,2,3,13,40,313,1833,27784,312227,9039597,194485968,10791499905,

%T 444739929613,47257907376576,3730171679762583,759195182636849001,

%U 114775951820515671520,44741688449064266073777

%N Number of n X n binary matrices, symmetric about both diagonal and antidiagonal, with no more than 3 ones in any 2 X 2 subblock.

%H R. H. Hardin, <a href="/A141511/b141511.txt">Table of n, a(n) for n = 0..24</a>

%K nonn

%O 0,2

%A _R. H. Hardin_, Aug 10 2008