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%I #5 Mar 31 2012 17:13:50
%S 10,208,8512,703744,117926752,40133444800,27783304021216,
%T 39171971918385184,112587925998400712032,660174283260849009031456
%N 1/4 the number of (n+1)X(n+1) 0..3 symmetric matrices with every 2X2 subblock having one, two or four distinct values
%e Some solutions for n=3
%e ..2..3..3..3....3..2..1..2....2..3..2..3....3..3..2..3....3..3..0..0
%e ..3..2..3..3....2..2..1..2....3..3..3..2....3..2..2..2....3..0..3..0
%e ..3..3..2..2....1..1..2..2....2..3..2..2....2..2..3..2....0..3..3..3
%e ..3..3..2..1....2..2..2..2....3..2..2..1....3..2..2..2....0..0..3..2
%K nonn
%O 1,1
%A _R. H. Hardin_ Mar 31 2012