A145952 - OEIS

A145952

Number of n X n binary arrays with all ones connected only in a zee 1,1 1,2 2,2 2,3 in any orientation.

%I #3 Mar 31 2012 12:35:08

%S 1,1,9,33,333,7127,205501,11166945,1122739259,190153543115,

%T 56969419979245,30406497496961445,28371939730808217655

%N Number of n X n binary arrays with all ones connected only in a zee 1,1 1,2 2,2 2,3 in any orientation.

%e Maximal 8 X 8 example

%e .0.1.0.1.1.0.0.0

%e .1.1.0.0.1.1.0.0

%e .1.0.0.0.0.0.1.0

%e .0.1.0.1.1.0.1.1

%e .0.1.1.0.1.1.0.1

%e .0.0.1.0.0.0.1.0

%e .1.1.0.1.1.0.1.1

%e .0.1.1.0.1.1.0.1

%K nonn

%O 1,3

%A _R. H. Hardin_, Oct 25 2008