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A209822 Number of (n+1) X 2 0..2 arrays with every 2 X 2 subblock having one or two distinct values, and new values 0..2 introduced in row major order. 1
8, 41, 218, 1169, 6278, 33725, 181178, 973337, 5229038, 28091861, 150917378, 810770609, 4355687798, 23399980205, 125711276618, 675356343497, 3628204270718, 19491734040581, 104715078744338, 562558861802849 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A209829.

LINKS

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

FORMULA

Empirical: a(n) = 6*a(n-1) - 3*a(n-2) - 2*a(n-3).

Empirical g.f.: x*(8 - 7*x - 4*x^2) / ((1 - x)*(1 - 5*x - 2*x^2)). - Colin Barker, Jul 13 2018

EXAMPLE

Some solutions for n=4:

..0..0....0..1....0..1....0..0....0..0....0..0....0..0....0..0....0..0....0..1

..1..1....0..0....0..0....0..0....0..1....0..1....1..1....0..1....0..0....1..0

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

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

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

CROSSREFS

Cf. A209829.

Sequence in context: A026978 A037577 A265149 * A051737 A209841 A196927

Adjacent sequences:  A209819 A209820 A209821 * A209823 A209824 A209825

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 13 2012

STATUS

approved

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Last modified November 21 14:18 EST 2019. Contains 329371 sequences. (Running on oeis4.)