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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. 1
256, 2292, 15564, 95408, 574364, 3472540, 21122008, 129099360, 792188532, 4877980340, 30132023264, 186677124664, 1159672904860, 7222244911020, 45083174298216, 282019092305744, 1767599836030724, 11098250929281124 (list; graph; refs; listen; history; text; internal format)
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

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Last modified January 17 09:54 EST 2020. Contains 330949 sequences. (Running on oeis4.)