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A228678 Number of nX3 binary arrays with no two ones adjacent horizontally, diagonally or antidiagonally. 1
5, 19, 77, 313, 1277, 5215, 21305, 87049, 355685, 1453363, 5938613, 24265921, 99153677, 405154783, 1655515121, 6764650225, 27641241413, 112945711027, 461510880221, 1885793543785, 7705597945181, 31486076453887, 128656207802537 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A228683

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. -x*(-5+6*x+3*x^2) / ( 1-5*x+3*x^2+3*x^3 ). - R. J. Mathar, Aug 31 2013

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Sequence in context: A323269 A268815 A108981 * A149771 A149772 A149773

Adjacent sequences:  A228675 A228676 A228677 * A228679 A228680 A228681

KEYWORD

nonn

AUTHOR

R. H. Hardin Aug 30 2013

STATUS

approved

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Last modified October 28 07:09 EDT 2021. Contains 348318 sequences. (Running on oeis4.)