A205911 Number of (n+1) X 3 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.

369, 1791, 9831, 60108, 387267, 2554848, 17051166, 114537918, 772431777, 5222734311, 35375284446, 239899338933, 1628261283648, 11057930844258, 75127872458898, 510566050100991, 3470474714680779, 23593143064954278

Offset

1,1

Comments

Column 2 of A205917.

Links

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

Formula

Empirical: a(n) = 16*a(n-1) -83*a(n-2) +110*a(n-3) +335*a(n-4) -960*a(n-5) -146*a(n-6) +2173*a(n-7) -531*a(n-8) -2598*a(n-9) +775*a(n-10) +2149*a(n-11) -993*a(n-12) -552*a(n-13) +306*a(n-14) for n>15.

Example

Some solutions for n=4:
..0..1..1....0..2..2....1..2..2....2..2..1....0..1..2....0..2..2....0..0..0
..0..1..2....2..1..0....1..1..2....1..2..2....0..1..1....0..1..2....2..2..0
..1..1..1....2..0..0....2..1..1....1..2..0....0..0..1....1..0..2....2..0..0
..0..0..0....0..2..1....1..1..2....1..2..2....2..0..0....1..2..2....0..0..1
..2..0..1....0..1..1....1..2..2....1..1..2....2..2..2....2..1..0....0..1..1

Crossrefs

Sequence in context: A251132 A183351 A275170 * A205903 A237844 A255202

Adjacent sequences: A205908 A205909 A205910 * A205912 A205913 A205914

Keyword

nonn

Author

R. H. Hardin, Feb 01 2012

Status

approved