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A184190
Half the number of (n+1) X 3 binary arrays with no 2 X 2 subblock containing exactly one 1.
1
19, 104, 561, 3050, 16581, 90185, 490546, 2668339, 14514611, 78953456, 429474355, 2336164665, 12707780398, 69125130363, 376012453567, 2045354053808, 11125890031367, 60520294171669, 329205663240430, 1790744248612871
OFFSET
1,1
COMMENTS
Column 2 of A184197.
LINKS
FORMULA
Empirical: a(n) = 7*a(n-1) - 7*a(n-2) - 10*a(n-3) + 10*a(n-4) + 2*a(n-5).
Empirical g.f.: x*(19 - 29*x - 34*x^2 + 41*x^3 + 8*x^4) / (1 - 7*x + 7*x^2 + 10*x^3 - 10*x^4 - 2*x^5). - Colin Barker, Apr 12 2018
EXAMPLE
Some solutions for 5 X 3:
..0..1..1....0..1..0....0..0..1....1..0..0....0..1..1....1..1..1....1..1..0
..1..0..1....1..0..1....0..0..1....1..0..0....1..1..1....0..0..1....1..0..1
..1..1..1....1..1..0....1..1..0....1..0..0....0..1..1....1..1..1....1..1..1
..1..1..0....0..0..1....1..1..0....0..1..1....1..1..0....1..1..1....0..1..0
..1..1..1....0..0..1....0..1..0....1..0..0....1..1..0....1..0..0....0..1..0
CROSSREFS
Cf. A184197.
Sequence in context: A195460 A195461 A096328 * A300644 A142300 A238108
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 10 2011
STATUS
approved