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

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

%S 0,63,28448,30822115,116038917572,1674154433221389,

%T 94771192355798810960,21139413071445258286746935,

%U 18590177181187681705139540637399,64457007154070058366630524024580865783

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

%H R. H. Hardin, <a href="/A210824/b210824.txt">Table of n, a(n) for n = 1..13</a>

%e Some solutions for n=3

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

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

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

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

%K nonn

%O 1,2

%A _R. H. Hardin_ Mar 27 2012