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A198205
Number of 2nX2 0..3 arrays with values 0..3 introduced in row major order and each element unequal to exactly two horizontal and vertical neighbors
1
4, 43, 658, 11029, 189376, 3272959, 56665678, 981535273, 17003856124, 294580477651, 5103458162314, 88415060881213, 1531751228239288, 26536907089886119, 459740106490112326, 7964792868501695569
OFFSET
1,1
COMMENTS
Column 1 of A198209
LINKS
FORMULA
Empirical: a(n) = 23*a(n-1) -103*a(n-2) +81*a(n-3)
EXAMPLE
Some solutions for n=3
..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1
..2..2....2..3....2..2....2..0....1..2....2..2....2..2....2..3....2..0....2..2
..1..1....2..3....1..1....2..0....1..2....0..0....3..3....2..3....2..0....0..1
..0..0....3..1....0..2....0..3....0..1....3..2....2..2....0..2....0..3....0..1
..1..1....3..1....0..2....0..3....0..1....3..2....1..1....0..2....0..3....2..2
..3..2....2..3....3..0....3..1....1..3....0..1....3..0....1..0....3..0....1..0
CROSSREFS
Sequence in context: A186768 A130545 A027311 * A277639 A326432 A074702
KEYWORD
nonn
AUTHOR
R. H. Hardin Oct 22 2011
STATUS
approved