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A186044
Number of (n+2) X 3 binary arrays with each 3 X 3 subblock singular.
1
338, 2038, 12278, 72802, 434174, 2588842, 15426974, 91951882, 548068238, 3266618650, 19470028382, 116047125514, 691674559982, 4122582893626, 24571800071294, 146455111766122, 872915295745934, 5202830428855834
OFFSET
1,1
COMMENTS
Column 1 of A186052.
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) + 4*a(n-2) + 18*a(n-3) - 40*a(n-4) - 24*a(n-5) - 72*a(n-6).
Empirical g.f.: 2*x*(169 + 174*x + 368*x^2 - 1412*x^3 - 1056*x^4 - 2304*x^5) / (1 - 5*x - 4*x^2 - 18*x^3 + 40*x^4 + 24*x^5 + 72*x^6). - Colin Barker, Apr 17 2018
EXAMPLE
Some solutions for 4 X 3:
..1..1..0....0..0..0....1..1..0....0..1..0....0..0..0....0..0..1....1..1..1
..0..0..0....0..1..0....1..1..0....1..1..0....0..1..1....0..1..1....0..0..0
..0..1..0....0..0..0....1..0..0....0..0..0....0..0..0....0..1..1....1..1..0
..1..1..1....0..0..1....0..1..0....1..0..0....0..0..0....0..0..1....1..1..1
CROSSREFS
Cf. A186052.
Sequence in context: A188213 A250802 A186052 * A070311 A205648 A221799
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 11 2011
STATUS
approved