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A229366 Number of n X 2 0..2 arrays avoiding 11 horizontally, 22 vertically and 00 antidiagonally. 1
8, 38, 184, 869, 4144, 19675, 93589, 444824, 2114934, 10054148, 47798953, 227238276, 1080310539, 5135871337, 24416324712, 116077006646, 551838764656, 2623482504621, 12472231233800, 59293915534091, 281887688707501 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) + 13*a(n-2) + 3*a(n-3) - 13*a(n-4) + 4*a(n-5).

Empirical g.f.: x*(8 + 22*x + 4*x^2 - 17*x^3 + 4*x^4) / (1 - 2*x - 13*x^2 - 3*x^3 + 13*x^4 - 4*x^5). - Colin Barker, Sep 14 2018

EXAMPLE

Some solutions for n=4:

  1 0   0 0   0 2   2 1   2 1   1 0   2 1   0 1   0 1   0 2

  1 0   1 0   0 0   0 2   0 1   1 0   0 0   1 2   0 2   2 0

  1 0   1 2   1 0   0 0   0 0   2 0   2 0   1 0   1 0   1 0

  1 0   2 0   2 0   1 2   2 0   1 2   1 0   2 2   1 2   2 0

CROSSREFS

Column 2 of A229372.

Sequence in context: A123518 A197338 A214931 * A007786 A026662 A196074

Adjacent sequences:  A229363 A229364 A229365 * A229367 A229368 A229369

KEYWORD

nonn

AUTHOR

R. H. Hardin, Sep 21 2013

STATUS

approved

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Last modified January 27 15:14 EST 2020. Contains 331295 sequences. (Running on oeis4.)