A141487 - OEIS

A141487

Number of n X n binary matrices, symmetric under 90-degree rotation, with no more than 1 one in any 2 X 2 subblock.

%I #9 Nov 25 2018 13:04:53

%S 1,2,1,3,4,13,17,82,167,1029,2594,22033,77729,874498,4050975,61638683,

%T 387821570,7893076251,66271702355,1814566347320,20521356444643,

%U 753627817663469,11423997447177546,563598221301212705

%N Number of n X n binary matrices, symmetric under 90-degree rotation, with no more than 1 one in any 2 X 2 subblock.

%H R. H. Hardin, Aug 09 2008, <a href="/A141487/b141487.txt">Table of n, a(n) for n = 0..30</a>

%K nonn

%O 0,2

%A _R. H. Hardin_, Aug 09 2008