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A205912
Number of (n+1) X 4 0..2 arrays with every 2 X 2 subblock having the same number of clockwise edge increases as its horizontal neighbors and the same number of counterclockwise edge increases as its vertical neighbors.
1
1764, 9831, 87918, 875760, 8986929, 93488811, 976932162, 10250633343, 107760730911, 1134683089512, 11958281270577, 126112581616143, 1330517219011788, 14041341384337191, 148208705188726647
OFFSET
1,1
COMMENTS
Column 3 of A205917.
LINKS
FORMULA
Empirical: a(n) = 16*a(n-1) -8*a(n-2) -775*a(n-3) +2020*a(n-4) +10484*a(n-5) -34209*a(n-6) -68090*a(n-7) +249504*a(n-8) +300963*a(n-9) -1131752*a(n-10) -899412*a(n-11) +3504902*a(n-12) +1424118*a(n-13) -6769192*a(n-14) -1246800*a(n-15) +7700896*a(n-16) +2186200*a(n-17) -6370208*a(n-18) -3919560*a(n-19) +5579640*a(n-20) +2517392*a(n-21) -3579296*a(n-22) -391776*a(n-23) +1328736*a(n-24) -428352*a(n-25) +34560*a(n-26) for n>32.
EXAMPLE
Some solutions for n=4:
..1..2..0..1....1..2..0..2....1..0..0..2....0..0..0..0....2..1..0..2
..2..2..0..0....1..2..2..2....1..0..2..2....2..2..2..2....1..2..1..0
..1..2..0..1....2..2..0..2....0..0..2..1....1..1..1..1....2..1..2..1
..2..2..0..0....2..0..0..0....2..2..2..2....2..2..1..2....0..2..0..2
..0..0..0..2....2..2..2..2....2..0..0..2....2..1..1..2....2..0..1..0
CROSSREFS
Sequence in context: A205731 A151769 A165678 * A237781 A205904 A061627
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 01 2012
STATUS
approved