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A207719 Number of 4 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 1 and 1 0 0 vertically. 1
9, 81, 387, 2205, 12015, 66339, 364869, 2009223, 11059965, 60888177, 335192787, 1845279405, 10158455727, 55923440859, 307864679445, 1694829122631, 9330221332989, 51363898889337, 282763934436339, 1556646681947805 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Row 4 of A207717.
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) +10*a(n-2) -8*a(n-3) -9*a(n-4) +6*a(n-5).
Empirical g.f.: 9*x*(1 - x)*(1 + 6*x + 3*x^2 - 6*x^3) / (1 - 4*x - 10*x^2 + 8*x^3 + 9*x^4 - 6*x^5). - Colin Barker, Jun 25 2018
EXAMPLE
Some solutions for n=4:
..1..0..1..0....1..0..1..0....1..1..0..0....0..1..0..1....1..0..1..1
..0..1..1..0....1..0..1..0....1..1..1..0....1..1..1..0....1..0..1..1
..1..0..1..0....1..0..1..0....1..0..1..0....0..1..0..1....1..0..1..1
..0..1..1..0....1..0..1..0....0..1..1..0....1..0..1..1....1..0..1..1
CROSSREFS
Cf. A207717.
Sequence in context: A207737 A221963 A207742 * A167717 A208079 A223719
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 19 2012
STATUS
approved

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Last modified April 14 18:28 EDT 2024. Contains 371667 sequences. (Running on oeis4.)