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%I #5 Mar 31 2012 17:12:53
%S 7,145,8869,1551481,784712137,1145192936557,4823916698572867,
%T 58647466694975620939,2057932010076596938468321,
%U 208422415794469123178956493563
%N 1/4 the number of (n+1)X(n+1) 0..3 symmetric matrices with every 2X2 subblock having one, three or four distinct values
%e Some solutions for n=3
%e ..2..0..2..1....2..1..1..2....3..1..2..0....2..0..1..2....1..0..3..0
%e ..0..1..3..1....1..0..3..0....1..0..1..1....0..3..2..3....0..3..1..0
%e ..2..3..2..1....1..3..1..3....2..1..3..2....1..2..1..0....3..1..2..2
%e ..1..1..1..0....2..0..3..2....0..1..2..0....2..3..0..3....0..0..2..2
%K nonn
%O 1,1
%A _R. H. Hardin_ Mar 31 2012
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