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A210821
Number of (n+1)X(n+1) 0..3 symmetric matrices containing all values 0..3 with every 2X2 subblock having one, two or four distinct values, and new values 0..3 introduced in lower triangle row major order
0
0, 5, 536, 69967, 14851443, 5745072271, 4267026118300, 6252252369058803, 18347836198388369328, 108778622095860972769932
OFFSET
1,2
EXAMPLE
Some solutions for n=3
..0..0..2..3....0..0..2..2....0..1..0..0....0..1..2..3....0..1..2..1
..0..1..3..2....0..1..3..3....1..1..1..0....1..0..3..2....1..0..3..0
..2..3..3..3....2..3..1..1....0..1..2..3....2..3..3..2....2..3..0..0
..3..2..3..1....2..3..1..2....0..0..3..2....3..2..2..2....1..0..0..1
CROSSREFS
Sequence in context: A067446 A249895 A241325 * A302222 A302668 A302470
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 27 2012
STATUS
approved