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A228655 Number of nX3 binary arrays with top left value 1 and no two ones adjacent horizontally, diagonally or antidiagonally. 1
2, 8, 34, 140, 574, 2348, 9598, 39224, 160282, 654944, 2676202, 10935332, 44683222, 182581508, 746051878, 3048465200, 12456425842, 50898577976, 207978216754, 849826072316, 3472499977390, 14189087019740, 57978456949582 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A228660

LINKS

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

FORMULA

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

Empirical: G.f. -2*x*(-1+x) / ( 1-5*x+3*x^2+3*x^3 ). - R. J. Mathar, Aug 29 2013

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Sequence in context: A111643 A000163 A117616 * A192402 A014445 A113440

Adjacent sequences:  A228652 A228653 A228654 * A228656 A228657 A228658

KEYWORD

nonn

AUTHOR

R. H. Hardin Aug 29 2013

STATUS

approved

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Last modified December 14 19:27 EST 2019. Contains 329987 sequences. (Running on oeis4.)