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A206270 Number of (n+1) X 2 0..2 arrays with no 2 X 2 subblock having the number of clockwise edge increases equal to the number of counterclockwise edge increases in its adjacent leftward or upward neighbors. 1
81, 306, 1233, 4884, 19509, 77580, 309057, 1230480, 4900461, 19512618, 77701857, 309412494, 1232105853, 4906303206, 19537226541, 77798456808, 309798343185, 1233636035952, 4912416015885, 19561547012604, 77895299289393 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A206277.

LINKS

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

FORMULA

Empirical: a(n) = 6*a(n-2) + 20*a(n-3) + 58*a(n-4) + 66*a(n-5) + 29*a(n-6) + 16*a(n-7).

Empirical g.f.: 3*x*(27 + 102*x + 249*x^2 + 476*x^3 + 431*x^4 + 174*x^5 + 88*x^6) / (1 - 6*x^2 - 20*x^3 - 58*x^4 - 66*x^5 - 29*x^6 - 16*x^7). - Colin Barker, Jun 15 2018

EXAMPLE

Some solutions for n=4:

..1..0....2..1....0..1....1..1....2..1....2..0....1..1....2..2....2..1....1..1

..0..2....2..0....2..0....1..0....1..1....1..2....0..1....1..2....0..2....1..2

..1..1....2..0....2..2....2..1....1..1....1..2....2..1....0..2....1..2....1..0

..2..0....2..1....1..0....2..2....0..1....1..0....0..2....2..0....2..2....2..1

..0..0....0..2....2..1....2..2....2..2....2..1....2..2....0..0....1..0....1..1

CROSSREFS

Cf. A206277.

Sequence in context: A206277 A236018 A206685 * A236011 A206678 A237463

Adjacent sequences:  A206267 A206268 A206269 * A206271 A206272 A206273

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 05 2012

STATUS

approved

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Last modified August 8 12:21 EDT 2022. Contains 356009 sequences. (Running on oeis4.)