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A203536
Number of nX2 0..2 arrays with every element neighboring horizontally or vertically both a 0 and a 1
2
0, 4, 4, 16, 64, 196, 676, 2304, 7744, 26244, 88804, 300304, 1016064, 3437316, 11628100, 39337984, 133079296, 450203524, 1523028676, 5152368400, 17430336576, 58966408900, 199481929956, 674842534144, 2282975946304, 7723252297476
OFFSET
1,2
COMMENTS
Column 2 of A203542
(A135491(n-2))^2 for n>=3
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) +3*a(n-2) +6*a(n-3) -a(n-4) -a(n-6)
EXAMPLE
Some solutions for n=5
..0..1....1..1....0..0....1..0....0..0....0..1....0..0....0..1....1..0....1..1
..0..1....0..0....1..1....1..0....1..1....0..1....1..1....0..1....1..0....0..0
..2..1....1..2....1..2....0..2....2..0....1..2....2..2....0..1....0..0....2..1
..0..0....1..0....0..0....0..1....1..0....1..0....0..0....0..0....0..1....0..1
..1..1....1..0....1..1....0..1....1..0....1..0....1..1....1..1....0..1....0..1
CROSSREFS
Sequence in context: A107382 A257622 A185567 * A375990 A038788 A010099
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 02 2012
STATUS
approved