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URL: https://oeis.org/A202464

⇱ A202464 - OEIS

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A202464
Number of (n+2) X 3 binary arrays with no more than two of any consecutive three bits set in any row or column.
2
265, 1573, 9253, 54085, 317179, 1858993, 10894297, 63850777, 374215201, 2193190681, 12853833343, 75333557377, 441513844561, 2587618272973, 15165477047269, 88881616706701, 520916142332515, 3052978074328417
OFFSET
1,1
COMMENTS
Column 1 of A202471.
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) +8*a(n-2) +18*a(n-3) -6*a(n-4) +2*a(n-5) -a(n-6).
Empirical g.f.: x*(265 + 513*x + 841*x^2 - 281*x^3 + 91*x^4 - 49*x^5) / (1 - 4*x - 8*x^2 - 18*x^3 + 6*x^4 - 2*x^5 + x^6). - Colin Barker, Jun 01 2018
EXAMPLE
Some solutions for n=4:
..0..1..0....1..0..0....1..0..0....0..0..0....1..0..1....0..0..0....0..1..1
..0..0..1....1..0..1....0..1..0....1..0..1....0..1..0....0..1..0....0..1..1
..0..1..0....0..1..0....0..1..0....1..0..0....0..0..0....1..1..0....1..0..0
..0..0..0....0..0..0....1..0..0....0..1..1....0..0..0....0..0..0....0..1..0
..0..1..1....0..0..1....0..1..0....0..1..1....0..1..1....0..0..0....1..1..0
..1..0..1....0..1..1....0..0..0....0..0..0....0..1..0....1..0..0....1..0..1
CROSSREFS
Cf. A202471.
Sequence in context: A259741 A202416 A202471 * A183247 A094795 A023043
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 19 2011
STATUS
approved