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A206047 Number of (n+1) X 2 0..2 arrays with the number of clockwise edge increases in every 2 X 2 subblock equal to one. 1
48, 255, 1338, 7041, 37020, 194691, 1023822, 5384085, 28313712, 148895799, 783011010, 4117687209, 21654034308, 113873925675, 598838568438, 3149163684861, 16560776867160, 87089576125791, 457985415203562 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A206054.

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) +7*a(n-2) -2*a(n-3).

Empirical g.f.: 3*x*(16 + 21*x - 6*x^2) / (1 - 4*x - 7*x^2 + 2*x^3). - Colin Barker, Jun 13 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Cf. A206054.

Sequence in context: A181773 A052683 A206054 * A223434 A235911 A235904

Adjacent sequences:  A206044 A206045 A206046 * A206048 A206049 A206050

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 03 2012

STATUS

approved

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Last modified December 6 13:24 EST 2021. Contains 349563 sequences. (Running on oeis4.)