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A282990
Number of nX2 0..1 arrays with no 1 equal to more than one of its horizontal and vertical neighbors.
5
4, 11, 33, 98, 291, 865, 2570, 7637, 22693, 67432, 200373, 595405, 1769236, 5257255, 15621845, 46420050, 137936399, 409875693, 1217938738, 3619084505, 10754048825, 31955475472, 94955158681, 282157659273, 838426745764, 2491370993875
OFFSET
1,1
COMMENTS
Column 2 of A282996, A295275.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) +3*a(n-2) -a(n-4).
Empirical: G.f.: -x*(-4-3*x+x^2+x^3)/(1-2*x-3*x^2+x^4) . - R. J. Mathar, Mar 02 2017
EXAMPLE
Some solutions for n=5
..0..0. .1..1. .1..0. .0..0. .1..1. .1..0. .0..1. .1..0. .1..0. .0..0
..0..1. .0..0. .1..0. .1..0. .0..0. .0..0. .1..0. .1..0. .0..0. .0..1
..1..0. .0..0. .0..1. .0..0. .0..0. .0..1. .0..0. .0..0. .0..0. .0..0
..0..1. .0..0. .1..0. .1..0. .0..0. .0..0. .0..0. .0..0. .0..1. .0..0
..0..0. .0..0. .0..0. .1..0. .1..1. .0..1. .0..0. .1..1. .1..0. .1..1
CROSSREFS
Sequence in context: A289973 A236583 A025191 * A099159 A116394 A259442
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 26 2017
STATUS
approved