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A210820
Number of (n+1)X(n+1) 0..3 symmetric matrices containing all values 0..3 with every 2X2 subblock having two or four distinct values, and new values 0..3 introduced in lower triangle row major order
0
0, 5, 350, 27048, 3100695, 592034865, 197411860692, 117689225496746, 126916285441085904, 249072860973467032724
OFFSET
1,2
EXAMPLE
Some solutions for n=3
..0..0..2..3....0..1..0..0....0..1..0..0....0..1..0..3....0..1..0..2
..0..1..3..3....1..1..1..1....1..1..1..0....1..1..1..2....1..1..0..2
..2..3..3..0....0..1..2..2....0..1..2..3....0..1..2..2....0..0..1..3
..3..3..0..3....0..1..2..3....0..0..3..3....3..2..2..3....2..2..3..1
CROSSREFS
Sequence in context: A300388 A269556 A227448 * A193806 A158105 A203527
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 27 2012
STATUS
approved