A206102 Number of (n+1) X 2 0..3 arrays with the number of clockwise edge increases in 2 X 2 subblocks nondecreasing, and counterclockwise edge increases nonincreasing, rightwards and downwards.

256, 2292, 15564, 95408, 574364, 3472540, 21122008, 129099360, 792188532, 4877980340, 30132023264, 186677124664, 1159672904860, 7222244911020, 45083174298216, 282019092305744, 1767599836030724, 11098250929281124

Offset

1,1

Comments

Column 1 of A206109.

Links

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

Formula

Empirical: a(n) = 16*a(n-1) - 87*a(n-2) + 174*a(n-3) - 15*a(n-4) - 420*a(n-5) + 607*a(n-6) - 346*a(n-7) + 72*a(n-8) for n>10.

Example

Some solutions for n=4:
..3..2....1..0....2..2....3..0....3..2....1..0....1..0....3..1....1..1....1..0
..0..1....3..1....3..1....1..1....0..0....3..2....0..1....0..0....2..2....0..0
..0..2....0..2....1..2....0..2....2..2....2..1....1..3....1..1....1..1....0..3
..3..3....1..3....1..3....3..3....1..1....3..2....3..0....1..2....1..2....3..3
..1..0....0..1....0..3....2..0....0..3....0..3....3..1....2..2....3..3....1..3

Crossrefs

Sequence in context: A235652 A235518 A206109 * A014713 A205642 A205635

Adjacent sequences: A206099 A206100 A206101 * A206103 A206104 A206105

Keyword

nonn

Author

R. H. Hardin, Feb 03 2012

Status

approved