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Number of (n+1)X(n+1) 0..3 symmetric matrices with every 2X2 subblock having one, two or three distinct values, and new values 0..3 introduced in lower triangle row major order
1

%I #5 Mar 31 2012 12:37:34

%S 5,171,33003,25302763,71285876395,732967188022763,

%T 27496666418419018091,3763456875799574658077867,

%U 1879339285974060290837281959275,3424008152076665406983529256359040747

%N Number of (n+1)X(n+1) 0..3 symmetric matrices with every 2X2 subblock having one, two or three distinct values, and new values 0..3 introduced in lower triangle row major order

%H R. H. Hardin, <a href="/A210832/b210832.txt">Table of n, a(n) for n = 1..11</a>

%e Some solutions for n=3

%e ..0..1..3..0....0..1..1..2....0..1..1..3....0..1..2..0....0..1..2..0

%e ..1..2..3..0....1..2..3..1....1..2..2..3....1..2..3..0....1..0..2..2

%e ..3..3..3..2....1..3..3..3....1..2..2..2....2..3..0..3....2..2..3..0

%e ..0..0..2..3....2..1..3..3....3..3..2..1....0..0..3..2....0..2..0..3

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 27 2012