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URL: https://oeis.org/A228386

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A228386
Number of n X 4 binary arrays with top left value 1 and no two ones adjacent horizontally or vertically.
1
3, 12, 72, 382, 2104, 11449, 62546, 341249, 1862631, 10165343, 55480071, 302792766, 1652555713, 9019158650, 49223917246, 268649627276, 1466210540982, 8002145144295, 43673350799304, 238356282199103, 1300878367732021
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) +9*a(n-2) -5*a(n-3) -4*a(n-4) +a(n-5).
Empirical g.f.: x*(3 - 3*x^2 + x^3) / (1 - 4*x - 9*x^2 + 5*x^3 + 4*x^4 - x^5). - Colin Barker, Sep 11 2018
EXAMPLE
Some solutions for n=4:
..1..0..0..0....1..0..1..0....1..0..1..0....1..0..1..0....1..0..1..0
..0..1..0..0....0..0..0..1....0..1..0..1....0..1..0..1....0..0..0..0
..1..0..1..0....1..0..1..0....0..0..0..0....1..0..1..0....1..0..1..0
..0..0..0..0....0..1..0..0....0..1..0..1....0..0..0..0....0..1..0..1
CROSSREFS
Column 4 of A228390.
Sequence in context: A335643 A277457 A367117 * A175836 A293138 A319948
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 21 2013
STATUS
approved