A206670 Number of (n+1) X 3 0..2 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.

360, 1812, 9318, 47106, 243432, 1242930, 6474150, 33323136, 173699544, 898948062, 4687777926, 24335901672, 126930698646, 660162473754, 3443416243986, 17928893882562, 93516332989608, 487232601543270, 2541312084390642

Offset

1,1

Comments

Column 2 of A206676.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +22*a(n-2) -59*a(n-3) -112*a(n-4) -136*a(n-5) +525*a(n-6) +182*a(n-7) -684*a(n-8) +417*a(n-9) +136*a(n-10) +252*a(n-11) +514*a(n-12) +224*a(n-13) +52*a(n-14) -80*a(n-15) -48*a(n-16).

Example

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

Crossrefs

Sequence in context: A112536 A140801 A236059 * A236991 A205514 A056390

Adjacent sequences: A206667 A206668 A206669 * A206671 A206672 A206673

Keyword

nonn

Author

R. H. Hardin, Feb 11 2012

Status

approved