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A209891 Number of (n+1)X3 0..2 arrays with every 2X2 subblock having two distinct values, and new values 0..2 introduced in row major order 1
34, 280, 2304, 19008, 156800, 1293568, 10671616, 88038400, 726296576, 5991780352, 49430814720, 407792893952, 3364197924864, 27753861939200, 228963000909824, 1888892288237568, 15582928518512640, 128555589286494208 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A209897

LINKS

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

FORMULA

Empirical: a(n) = 8*a(n-1) +4*a(n-2) -16*a(n-3).

Empirical G.f.: 2*x*(17+4*x-36*x^2)/(1-8*x-4*x^2+16*x^3). [Colin Barker, Mar 15 2012]

EXAMPLE

Some solutions for n=4

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

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

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

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

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

CROSSREFS

Sequence in context: A301543 A252999 A229327 * A027006 A156531 A220565

Adjacent sequences:  A209888 A209889 A209890 * A209892 A209893 A209894

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 14 2012

STATUS

approved

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Last modified May 24 16:47 EDT 2019. Contains 323533 sequences. (Running on oeis4.)