A210857 - OEIS

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

%S 4,94,6400,1265336,726175112,1209791788480,5850732722422240,

%T 82137354029529991584,3347356112567824150084288,

%U 395998823277275732737683780672,135993026862887355613684481546308800

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

%H R. H. Hardin, <a href="/A210857/b210857.txt">Table of n, a(n) for n = 1..14</a>

%e Some solutions for n=3

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 28 2012