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.

2120, 25512, 310912, 3825072, 47118720, 583496376, 7243545064, 90103381160, 1122611538952, 14001936459304, 174794369231840, 2183353242022088, 27285297768268712, 341092545413648936, 4265101329518123760

Offset

1,1

Comments

Column 2 of A205954.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

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

Adjacent sequences: A205946 A205947 A205948 * A205950 A205951 A205952

Keyword

nonn

Author

R. H. Hardin, Feb 02 2012

Status

approved