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A205219
Number of (n+1)X2 0..1 arrays with the number of equal 2X2 subblock diagonal pairs and equal antidiagonal pairs differing from each horizontal or vertical neighbor, and new values 0..1 introduced in row major order
2
8, 20, 52, 132, 340, 868, 2228, 5700, 14612, 37412, 95860, 245508, 628948, 1610980, 4126772, 10570692, 27077780, 69360548, 177671668, 455113860, 1165800532, 2986255972, 7649458100, 19594481988, 50192314388, 128570242340, 329339499892
OFFSET
1,1
COMMENTS
Column 1 of A205226
LINKS
FORMULA
Empirical: a(n) = a(n-1) +4*a(n-2).
Empirical g.f.: 4*x*(2+3*x)/(1-x-4*x^2). - R. J. Mathar, Jun 18 2013
EXAMPLE
Some solutions for n=4
..0..1....0..0....0..1....0..0....0..0....0..0....0..1....0..0....0..0....0..1
..1..1....1..0....1..0....1..0....0..0....1..0....1..1....1..1....0..0....0..1
..0..0....1..0....0..0....0..1....1..0....1..0....1..1....1..0....0..1....0..0
..1..0....1..1....1..1....1..1....1..0....0..0....0..0....0..1....1..0....0..0
..0..1....0..0....0..1....1..1....0..0....0..0....0..0....0..0....1..0....1..0
CROSSREFS
Sequence in context: A107816 A361073 A361215 * A232401 A036835 A295933
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 23 2012
STATUS
approved