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A205949
Number of (n+1) X 3 0..3 arrays with no 2 X 2 subblock having the same number of clockwise edge increases as its horizontal neighbors or the same number of counterclockwise edge increases as its vertical neighbors.
1
2120, 25512, 310912, 3825072, 47118720, 583496376, 7243545064, 90103381160, 1122611538952, 14001936459304, 174794369231840, 2183353242022088, 27285297768268712, 341092545413648936, 4265101329518123760
OFFSET
1,1
COMMENTS
Column 2 of A205954.
LINKS
FORMULA
Empirical: a(n) = 13*a(n-1) +95*a(n-2) -1350*a(n-3) +28*a(n-4) +12273*a(n-5) +18204*a(n-6) -111624*a(n-7) -209410*a(n-8) +1307833*a(n-9) -502763*a(n-10) -5304545*a(n-11) +2475932*a(n-12) +18018847*a(n-13) +9204627*a(n-14) -86685214*a(n-15) +29263635*a(n-16) +184054379*a(n-17) -181331648*a(n-18) -316335299*a(n-19) +298579727*a(n-20) +470531838*a(n-21) -208962550*a(n-22) -280087665*a(n-23) +149755402*a(n-24) +356599738*a(n-25) -322601454*a(n-26) -78352792*a(n-27) +123710256*a(n-28) +45763920*a(n-29) +961136*a(n-30) +43332544*a(n-31) +17727680*a(n-32) +11389440*a(n-33) +2708480*a(n-34) -2657280*a(n-35) -214016*a(n-36) for n>37.
EXAMPLE
Some solutions for n=4:
..1..0..0....2..1..1....2..0..1....1..2..0....2..0..1....2..1..0....1..1..2
..3..1..3....3..2..0....0..3..2....0..2..0....0..3..2....1..0..0....2..1..0
..1..1..0....2..2..1....0..0..3....2..3..3....0..0..3....0..0..0....0..3..0
..3..0..3....2..2..3....0..0..0....0..3..1....0..0..3....1..2..1....0..3..1
..1..0..3....1..1..3....2..0..0....1..2..0....0..1..0....0..2..3....1..0..0
CROSSREFS
Sequence in context: A031680 A031544 A205660 * A205460 A263510 A250970
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 02 2012
STATUS
approved